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1.	Anasontzis, George E, 1980 (författare) Biomass modifying enzymes: From discovery to application 2012 Ingår i: Oral presentation at the Chalmers Life Science AoA conference. Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract It has now been realized that the road towards the bio-based economy is a one-way street, leaving gradually the oil-based technology and driving slowly towards a more sustainable society. The current non-biodegradable hydrocarbon fuels and plastics will be replaced by new products which will derive from natural and renewable resources. The synthesis of such biofuels and biochemicals is still challenged by the difficulties to cost efficiently degrade lignocellulosic material to fermentable sugars or to isolate the intact polymers. Biomass degrading and modifying enzymes play an integral role both in the separation of the polymers from the wood network, as well as in their subsequent modification, prior to further product development.Our group interests focus on all levels of applied enzyme research of biomass acting enzymes: Discovery, assay development, production and application. Relevant examples will be provided: What is our strategy for discovering novel microorganisms and enzymes from the tropical forests and grasslands of Vietnam? How do we design novel real-world assays for enzyme activity determination? Which are the bottlenecks in the enzymatic cellulose hydrolysis? How enzymes can be used to produce high added value compounds from biomass?
2.	Systems Perspectives on Biorefineries 2012 2012 Samlingsverk (redaktörskap) (refereegranskat)abstract Replacing fossil fuels with biomass for the production of energy carriers, materials and specialty chemicalsis a challenge that now confronts humanity. In which applications shall we use limited resourcesof biomass? How can biomass be refined into the products we want? What is an optimal design of abiorefinery? How is the most advantageous portfolio of policy instruments designed to realise the biorefineriesof the future?There is not one final answer to these questions. However, different systems studies can provide us withcomplementary pieces of the puzzle. These can be valuable by themselves, or be brought together into alarger and more complex picture. Systems perspectives on Biorefineries 2012 contains nine chapters thataddress different topics related to the immensely important issue of how the world’s biomass resourcescan, or should, be converted into the goods we need and desire. The book is far from complete, but it is acontribution and a start...
3.	Ask, Magnus, 1983 (författare) Towards More Robust Saccharomyces cerevisiae Strains for Lignocellulosic Bioethanol Production: Lessons from process concepts and physiological investigations 2013 Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract Dwindling oil reserves and the negative impacts of fossil fuels on the environment call for more sustainable energy sources. First-generation bioethanol produced from sugar cane and corn has met some of these needs, but it competes with the food supply for raw materials. Lignocellulosic biomass is an abundant non-edible raw material that can be converted to ethanol using the yeast Saccharomyces cerevisiae. However, due to the inherent recalcitrance to degradation of lignocellulosic raw materials, harsh pretreatment methods must be used to liberate fermentable sugars, resulting in the release of compounds such as acetic acid, furan aldehydes and phenolics, that inhibit yeast metabolism. This thesis research aimed to identify bottlenecks in terms of inhibitory compounds related to ethanol production from two lignocellulosic raw materials, Arundo donax and spruce, and furthermore to harness the physiological responses to these inhibitors to engineer more robust yeast strains. A comparative study of separate hydrolysis and fermentation (SHF) and simultaneous saccharification and fermentation (SSF) revealed that acetic acid limits xylose utilization in pretreated Arundo donax, whereas the furan aldehydes furfural and 5-hydroxymethyl-2-furaldehyde (HMF) were hypothesized to be key inhibitors in pretreated spruce. The impacts of furfural and HMF on the redox and energy metabolism of S. cerevisiae were studied in detail in chemostat and batch cultivations. After adding the inhibitors to the feed medium of chemostat cultivations, the intracellular levels of NADH, NADPH, and ATP were found to decrease by 40, 75, and 19%, respectively, suggesting that furan aldehydes drain the cells of reducing power. A strong effect on redox metabolism was also observed after pulsing furfural and HMF in the xylose consumption phase in batch cultures. The drainage of reducing power was also observed in a genome-wide study of transcription that found that genes related to NADPH-requiring processes, such as nitrogen and sulphur assimilation, were significantly induced. The redox metabolism was engineered by overproducing the protective metabolite and antioxidant glutathione. Strains with an increased intracellular level of reduced glutathione were found to sustain ethanol production for longer duration in SSF of pretreated spruce, yielding 70% more ethanol than did the wild type strain.
4.	Ylitervo, Päivi (författare) Concepts for improving ethanol productivity from lignocellulosic materials : encapsulated yeast and membrane bioreactors 2014 Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract Lignocellulosic biomass is a potential feedstock for production of sugars, which can be fermented into ethanol. The work presented in this thesis proposes some solutions to overcome problems with suboptimal process performance due to elevated cultivation temperatures and inhibitors present during ethanol production from lignocellulosic materials. In particular, continuous processes operated at high dilution rates with high sugar utilisation are attractive for ethanol fermentation, as this can result in higher ethanol productivity. Both encapsulation and membrane bioreactors were studied and developed to achieve rapid fermentation at high yeast cell density. My studies showed that encapsulated yeast is more thermotolerant than suspended yeast. The encapsulated yeast could successfully ferment all glucose during five consecutive batches, 12 h each at 42 °C. In contrast, freely suspended yeast was inactivated already in the second or third batch. One problem with encapsulation is, however, the mechanical robustness of the capsule membrane. If the capsules are exposed to e.g. high shear forces, the capsule membrane may break. Therefore, a method was developed to produce more robust capsules by treating alginate-chitosan-alginate (ACA) capsules with 3-aminopropyltriethoxysilane (APTES) to get polysiloxane-ACA capsules. Of the ACA-capsules treated with 1.5% APTES, only 0–2% of the capsules broke, while 25% of the untreated capsules ruptured within 6 h in a shear test. In this thesis membrane bioreactors (MBR), using either a cross-flow or a submerged membrane, could successfully be applied to retain the yeast inside the reactor. The cross-flow membrane was operated at a dilution rate of 0.5 h-1 whereas the submerged membrane was tested at several dilution rates, from 0.2 up to 0.8 h-1. Cultivations at high cell densities demonstrated an efficient in situ detoxification of very high furfural levels of up to 17 g L-1 in the feed medium when using a MBR. The maximum yeast density achieved in the MBR was more than 200 g L-1. Additionally, ethanol fermentation of nondetoxified spruce hydrolysate was possible at a high feeding rate of 0.8 h-1 by applying a submerged membrane bioreactor, resulting in ethanol productivities of up to 8 g L-1 h-1. In conclusion, this study suggests methods for rapid continuous ethanol production even at stressful elevated cultivation temperatures or inhibitory conditions by using encapsulation or membrane bioreactors and high cell density cultivations.
5.	Ylitervo, Päivi, et al. (författare) Continuous Ethanol Production with a Membrane Bioreactor at High Acetic Acid Concentrations 2014 Ingår i: Membranes. - : MDPI. - 2077-0375. ; 4:3, s. 372-387 Tidskriftsartikel (refereegranskat)abstract The release of inhibitory concentrations of acetic acid from lignocellulosic raw materials during hydrolysis is one of the main concerns for 2nd generation ethanol production. The undissociated form of acetic acid can enter the cell by diffusion through the plasma membrane and trigger several toxic effects, such as uncoupling and lowered intracellular pH. The effect of acetic acid on the ethanol production was investigated in continuous cultivations by adding medium containing 2.5 to 20.0 g•L−1 acetic acid at pH 5.0, at a dilution rate of 0.5 h−1. The cultivations were performed at both high (~25 g•L−1) and very high (100–200 g•L−1) yeast concentration by retaining the yeast cells inside the reactor by a cross-flow membrane in a membrane bioreactor. The yeast was able to steadily produce ethanol from 25 g•L−1 sucrose, at volumetric rates of 5–6 g•L−1•h−1 at acetic acid concentrations up to 15.0 g•L−1. However, the yeast continued to produce ethanol also at a concentration of 20 g•L−1 acetic acid but at a declining rate. The study thereby demonstrates the great potential of the membrane bioreactor for improving the robustness of the ethanol production based on lignocellulosic raw materials.
6.	Brandin, Jan, 1958- (författare) Usage of Biofuels in Sweden 2013 Ingår i: CSR-2 Catalyst for renewable sources. - Novosibrisk, Russia : Boreskov Institute of Catalysis. - 9785990255777 ; , s. 5-7 Konferensbidrag (refereegranskat)abstract In Sweden, biofuels have come into substantial use, in an extent that are claimed to be bigger than use of fossil oil. One driving force for this have been the CO2-tax that was introduced in 1991 (1). According to SVEBIO:s calculations (2) based on the Swedish Energy Agency´s prognosis, the total energy consumption in Sweden 2012 was 404 TWh. If the figure is broken down on the different energy sources (figure 1) one can see that the consumption roughly distribute in three different, equally sized, blocks, Biofuels, fossil fuels and water & nuclear power. The major use of the fossil fuels is for transport and the water & nuclear power is used as electric power. The main use of the biofuels is for heating in the industrial sector and as district heating. In 2009 the consumption from those two segments was 85 TWh, and 10 TWh of bio power was co-produced giving an average biomass to electricity efficiency of 12%. This indicates a substantial conversion potential from hot water production to combined heat and power (CHP) production. in Sweden 2013 broken down on the different energy sources. In 2006 the pulp, paper and sawmill industry accounted for 95% of the bio energy consumption in the industrial sector, and the major biofuel consumed was black liquor (5). However, the pulp and paper industries also produced the black liquor in their own processes. The major energy source (58%) for district heating during 2006 was woody biomass (chips, pellets etc.) followed by waste (24%), peat (6%) and others (12%) (5). The use of peat has probably decreased since 2006 since peat is no longer regarded as a renewable energy source. While the use of biofuel for heating purpose is well developed and the bio-power is expected to grow, the use in the transport sector is small, 9 TWh or 7% in 2011. The main consumption there is due to the mandatory addition (5%) of ethanol to gasoline and FAME to diesel (6). The Swedish authorities have announced plans to increase the renewable content to 7.5 % in 2015 on the way to fulfill the EU’s goal of 10 % renewable transportation fuels in 2020. However the new proposed fuel directive in EU says that a maximum of 5% renewable fuel may be produced from food sources like sugars and vegetable oils. Another bothersome fact is that, in principle, all rape seed oil produced in Sweden is consumed (95-97%) in the food sector, and consequently all FAME used (in principle) in Sweden is imported as FAME, rape seed oil or seed (6). In Sweden a new source of biodiesel have emerged, tall oil diesel. Tall oil is extracted from black liquor and refined into a diesel fraction (not FAME) and can be mixed into fossil diesel, i.e. Preem Evolution diesel. The SUNPINE plant in Piteå have a capacity of 100 000 metric tons of tall oil diesel per annum, while the total potential in all of Sweden is claimed to be 200 000 tons (7). 100 000 tons of tall oil corresponds to 1% of the total diesel consumption in Sweden. in Sweden for 2010 and a prognosis for 2014. (6). Accordingly, the profoundest task is to decrease the fossil fuel dependency in the transport sector, and clearly, the first generation biofuels can´t do this on its own. Biogas is a fuel gas with high methane content that can be used in a similar way to natural gas; for instance for cooking, heating and as transportation fuel. Today biogas is produced by fermentation of waste (municipal waste, sludge, manure), but can be produced by gasification of biomass, for instance from forest residues such as branches and rots (GROT in Swedish). To get high efficiency in the production, the lower hydrocarbons, mainly methane, in the producer gas, should not be converted into synthesis gas. Instead a synthesis gas with high methane content is sought. This limits the drainage of chemically bonded energy, due to the exothermic reaction in the synthesis step (so called methanisation). In 2011 0.7 TWh of biogas was produced in Sweden by fermentation of waste (6) and there were no production by gasification, at least not of economic importance. The potential seems to be large, though. In 2008 the total potential for biogas production, in Sweden, from waste by fermentation and gasification was estimated to 70 TWh (10 TWh fermentation and 60 TWh gasification) (8). This figure includes only different types of waste and no dedicated agricultural crops or dedicated forest harvest. Activities in the biogas sector, by gasification, in Sweden are the Göteborgs energi´s Gobigas project in Gothenburg and Eon´s Bio2G-project, now pending, in south of Sweden. If the producer gas is cleaned and upgraded into synthesis gas also other fuels could be produced. In Sweden methanol and DME productions are planned for in the Värmlands metanol-project and at Chemrecs DME production plant in Piteå.
7.	Svensson, Helena, et al. (författare) Modeling of soot formation during partial oxidation of producer gas 2013 Ingår i: Fuel. - : Elsevier. - 0016-2361 .- 1873-7153. ; 106, s. 271-278 Tidskriftsartikel (refereegranskat)abstract Soot formation in a reverse-flow partial-oxidation reactor for reforming of gasifier producer gas has been studied. The process was modeled using a detailed reaction mechanism to describe the kinetics of soot formation. The numerical model was validated against experimental data from the literature and showed good agreement with reported data. Nine cases with different gas compositions were simulated in order to study the effects of water, hydrogen and methane content of the gas. The CO and CO2 contents, as well as the tar content of the gas, were also varied to study their effects on soot formation. The results showed that the steam and hydrogen content of the inlet gas had less impact on the soot formation than expected, while the methane content greatly influenced the soot formation. Increasing the CO2 content of the gas reduced the amount of soot formed and gave a higher energy efficiency and methane conversion. In the case of no tar in the incoming gas the soot formation was significantly reduced. It can be concluded that removing the tar in an energy efficient way, prior to the partial oxidation reactor, will greatly reduce the amount of soot formed. Further investigation of tar reduction is needed and experimental research into this process is ongoing.
8.	Anasontzis, George E, 1980 (författare) New lignocellulolytic enzymes for feed and bio-ethanol production from agricultural waste 2013 Ingår i: Lignocellulolytic enzymes, Production & Applications, Ba Vi, Hanoi, November 1-2, 2013. Konferensbidrag (övrigt vetenskapligt/konstnärligt)
9.	Olofsson, Martin, 1975-, et al. (författare) Combined Effects of Nitrogen Concentration and Seasonal Changes on the Production of Lipids in Nannochloropsis oculata 2014 Ingår i: Marine Drugs. - Basel, Switzerland : MDPI AG. - 1660-3397. ; 12:4, s. 1891-1910 Tidskriftsartikel (refereegranskat)abstract Instead of sole nutrient starvation to boost algal lipid production, we addressed nutrient limitation at two different seasons (autumn and spring) during outdoor cultivation in flat panel photobioreactors. Lipid accumulation, biomass and lipid productivity and changes in fatty acid composition of Nannochloropsis oculata were investigated under nitrogen (N) limitation (nitrate:phosphate N:P 5, N:P 2.5 molar ratio). N. oculata was able to maintain a high biomass productivity under N-limitation compared to N-sufficiency (N:P 20) at both seasons, which in spring resulted in nearly double lipid productivity under N-limited conditions (0.21 g L−1 day−1) compared to N-sufficiency (0.11 g L−1 day−1). Saturated and monounsaturated fatty acids increased from 76% to nearly 90% of total fatty acids in N-limited cultures. Higher biomass and lipid productivity in spring could, partly, be explained by higher irradiance, partly by greater harvesting rate (~30%). Our results indicate the potential for the production of algal high value products (i.e., polyunsaturated fatty acids) during both N-sufficiency and N-limitation. To meet the sustainability challenges of algal biomass production, we propose a dual-system process: Closed photobioreactors producing biomass for high value products and inoculum for larger raceway ponds recycling waste/exhaust streams to produce bulk chemicals for fuel, feed and industrial material.
10.	Olsson, Lisbeth, 1963, et al. (författare) Linking growth on lignocellulosic carbon sources to gene expression through secretome analysis in novel enzyme producing filamentous fungi from Vietnamese habitats 2013 Ingår i: 35th Symposium on Biotechnology for Fuels and Chemicals. Konferensbidrag (övrigt vetenskapligt/konstnärligt)
11.	Legrand, Catherine, et al. (författare) Growing algae in Scandinavia : utopia or opportunity? 2011 Ingår i: Algae: The sustainable biomass for the future.. - Berlin, Germany : s.Pro sustainable projects GmbH. ; , s. 16-17 Konferensbidrag (populärvet., debatt m.m.)
12.	Nordlander, Eva, et al. (författare) Modeling of a full-scale biogas plant using a dynamic neural network 2013 Konferensbidrag (refereegranskat)
13.	Brandin, Jan, 1958-, et al. (författare) Small Scale Gasifiction : Gas Engine CHP for Biofuels 2011 Rapport (övrigt vetenskapligt/konstnärligt)abstract In a joint project, Linnaeus University in Växjö (LNU) and the Faculty of Engineering at Lund University (LTH) were commissioned by the Swedish Energy Agency to make an inventory of the techniques and systems for small scale gasifier-gas engine combined heat and power (CHP) production and to evaluate the technology. Small scale is defined here as plants up to 10 MWth, and the fuel used in the gasifier is some kind of biofuel, usually woody biofuel in the form of chips, pellets, or sawdust. The study is presented in this report. The report has been compiled by searching the literature, participating in seminars, visiting plants, interviewing contact people, and following up contacts by e-mail and phone. The first, descriptive part of the report, examines the state-of-the-art technology for gasification, gas cleaning, and gas engines. The second part presents case studies of the selected plants: Meva Innovation’s VIPP-VORTEX CHP plant DTU’s VIKING CHP plant Güssing bio-power station Harboøre CHP plant Skive CHP plant The case studies examine the features of the plants and the included unit operations, the kinds of fuels used and the net electricity and overall efficiencies obtained. The investment and operating costs are presented when available as are figures on plant availability. In addition we survey the international situation, mainly covering developing countries. Generally, the technology is sufficiently mature for commercialization, though some unit operations, for example catalytic tar reforming, still needs further development. Further development and optimization will probably streamline the performance of the various plants so that their biofuel-to-electricity efficiency reaches 30-40 % and overall performance efficiency in the range of 90 %. The Harboøre, Skive, and Güssing plant types are considered appropriate for municipal CHP systems, while the Viking and VIPP-VORTEX plants are smaller and considered appropriate for replacing hot water plants in district heating network. The Danish Technical University (DTU) Biomass Gasification Group and Meva International have identified a potentially large market in the developing countries of Asia. Areas for suggested further research and development include: Gas cleaning/upgrading Utilization of produced heat System integration/optimization Small scale oxygen production Gas engine developments
14.	Bettiga, Maurizio, 1978, et al. (författare) Robust S. cerevisiae strain for next generation bio-processes: concepts and case-studies 2013 Ingår i: Cell Factories and Biosustainability (Hilleroed, Denmark, May 5-8 2013). Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract The realization of an oil independent economy relies on the development of competitive processes for the production of fuels and chemicals from renewable resources. The extensive research on second-generation ethanol has paved the way to a new concept of bio-based industry, where lignocellulosic material is the primary source of sugars, to be converted to a number of fuels and chemicals. Harsh conditions during the bioconversion of lignocellulose-derived sugars to the desired products drastically hamper cell viability and therefore productivity. Microbial inhibition limits bioprocesses to an extent such that it can be said that understanding and harnessing microbial robustness is a prerequisite for the feasibility of new bioprocess and the production of renewable fuels and chemicals.Current research carried out by our group focuses on the yeast Saccharomyces cerevisiae and aims at investigating the molecular bases of microbial robustness. Our efforts include the identification of the molecular targets of different classes of fermentation inhibitors aiming at understanding the complex responses of the cells to these compounds. The final goal is to engineer more robust strains. The concept of robustness will be discussed and examples of key features for S. cerevisiae robustness as well as examples of successful engineering to increase robustness will be presented.
15.	Bettiga, Maurizio, 1978, et al. (författare) Robust S. cerevisiae strain for next generation bio-processes: concepts and case-studies 2013 Ingår i: 35th Symposium on Biotechnology for Fuels and Chemicals (Portland, OR. April 29-May 2, 2013). Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract The realization of an oil independent economy relies on the development of competitive processes for the production of fuels and chemicals from renewable resources. The extensive research on second-generation ethanol has paved the way to a new concept of bio-based industry, where lignocellulosic material is the primary source of sugars, to be converted to a number of fuels and chemicals. Sugars are released from cellulose and hemicellulose by pretreatment and hydrolysis steps. Harsh conditions result in the formation of a number of compounds, originating from sugars and lignin breakdown and acting as microorganism inhibitors. Weak organic acids, furaldehydes and phenolic compounds are sources of stress for the fermenting microorganism, as they influence cellular metabolism in a number of ways, including direct damage on cellular functions or by perturbations of the cellular energy and redox metabolism. In addition, the product of interest can act as a potent inhibitor. Regardless of the product, robust microorganisms are a prerequisite for the feasibility of lignocellulose-based bioprocesses.Current research carried out by our group focuses on the yeast Saccharomyces cerevisiae and aims at investigating the molecular bases of microbial robustness. Our efforts include the identification of the molecular targets of different classes of fermentation inhibitors aiming at understanding the complex responses of the cells to these compounds. The final goal is to engineer more robust strains. The concept of robustness will be discussed and examples of key features for S. cerevisiae robustness as well as examples of successful engineering to increase robustness will be presented.
16.	Westman, Johan (författare) Ethanol production from lignocellulose using high local cell density yeast cultures. Investigations of flocculating and encapsulated Saccharomyces cerevisiae 2014 Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract Efforts are made to change from 1st to 2nd generation bioethanol production, using lignocellulosics as raw materials rather than using raw materials that alternatively can be used as food sources. An issue with lignocellulosics is that a harsh pretreatment step is required in the process of converting them into fermentable sugars. In this step, inhibitory compounds such as furan aldehydes and carboxylic acids are formed, leading to suboptimal fermentation rates. Another issue is that lignocellulosics may contain a large portion of pentoses, which cannot be fermented simultaneously with glucose by Saccharomyces cerevisiae. In this thesis, high local cell density has been investigated as a means of overcoming these two issues. Encapsulation of yeast in semi-permeable alginate-chitosan capsules increased the tolerance towards furan aldehydes, but not towards carboxylic acids. The selective tolerance can be explained by differences in the concentration of compounds radially through the cell pellet inside the capsule. For inhibitors, gradients will only be formed if the compounds are readily convertible, like the furan aldehydes. Conversion of inhibitors by cells close to the membrane leads to decreased concentrations radially through the cell pellet. Thus, cells closer to the core experience subinhibitory levels of inhibitors and can ferment sugars. Carbohydrate gradients also give rise to nutrient limitations, which in turn trigger a stress response in the yeast, as was observed on mRNA and protein level. The stress response is believed to increase the robustness of the yeast and lead to improved tolerance towards additional stress. Glucose and xylose co-consumption by a recombinant strain, CEN.PK XXX, was also improved by encapsulation. Differences in affinity of the sugar transporters normally result in that glucose is taken up preferentially to xylose. However, when encapsulated, cells in different parts of the capsule experienced high and low glucose concentrations simultaneously. Xylose and glucose could thus be taken up concurrently. This improved the co-utilisation of the sugars by the system and led to 50% higher xylose consumption and 15% higher final ethanol titres. A protective effect by the capsule membrane itself could not be shown. Hence, the interest in flocculation was triggered, as a more convenient way to keep the cells together. To investigate whether flocculation increases the tolerance, like encapsulation, recombinant flocculating yeast strains were constructed and compared with the non-flocculating parental strain. Experiments showed that strong flocculation did not increase the tolerance towards carboxylic acids. However, the tolerance towards a spruce hydrolysate and especially against furfural was indeed increased. The results of this thesis show that high local cell density yeast cultures have the potential to aid against two of the major problems for 2nd generation bioethanol production: inhibitors and simultaneous hexose and pentose utilisation.
17.	Adeboye, Peter, 1982, et al. (författare) DETOXIFICATION AS A STRATEGY FOR DEVELOPING TOLERANCE IN Saccharomyces cerevisiae TO PHENOLIC COMPOUNDS 2014 Ingår i: ISSY31: 31ST INTERNATIONAL SPECIALISED SYMPOSIUM ON YEAST. Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract Several phenolic compounds are formed as products of lignin breakdown during pretreatment of lignocellulosic biomass. These phenolic compounds are inhibitory to cell growth and function as biocatalysts in the production of second generation biofuels from degraded lignocellulosic biomass. Our research is focused on developing a Saccharomyces cerevisiae strain with improved resistance to phenolic compounds.As part of our study, we have focused on understanding the ability of S. cerevisiae to tolerate and convert phenolic compounds. We aim to understand the conversion mechanisms of phenolic compounds and adapt the knowledge to the engineering and use of S. cerevisiae on a biotechnological platform for bioethanol production and prospective, novel bio-based chemicals.We have investigated toxicity of various phenolic compounds against S. cerevisiae. Our results showed that phenolic compounds have varied toxicity against S. cerevisiae and the toxicity may be dependent on the structure of the compound involved. Under aerobic batch cultivation conditions, we have also studied the conversion of phenolic compounds by S. cerevisiae using coniferyl aldehyde, ferulic acid and p-coumaric acid as representative phenolic compounds. We compiled a list of conversion products of the three starting compounds under investigation and we proposed a possible conversion pathway, currently being investigated.In this talk, we present the proposed conversion pathway through which S. cerevisiae converts and detoxifies coniferyl aldehyde, ferulic acid and p-coumaric acid under aerobic cultivation condition.
18.	Marx, Christian, 1975, et al. (författare) ENGINEERING GLUTATHIONE BIOSYNTHESIS TO ENHANCE REDOX ROBUSTNESS OF Saccharomyces cerevisiae 2014 Ingår i: ISSY31: 31ST INTERNATIONAL SPECIALISED SYMPOSIUM ON YEAST. Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract The focus for biofuel production shifts to using lignocellulose biomass from forest and agricultural by-products since it does not compete with food and feed production. Polysaccharides must be pretreated to be made accessible to hydrolytic enzymes to generate monomeric sugars for the following fermentation. In this pretreatment step inhibitors of fermenting microorganisms are generated, mainly furan derivates, weak acids and phenolics. Although Saccharomyces cerevisiae is more robust than bacteria, there is demand for improvement and the development of novel yeast strains with increased inhibitor tolerance is highly desirable.Furan derivates and other inhibitors have been shown to induce the formation of reactive oxygen species. Engineering of the redox metabolism of S. cerevisiae in terms of increasing the intracellular levels of glutathione by overexpressing glutathione synthetase GSH1 resulted in increased strain robustness in a simultaneous saccharification and fermentation (SSF) process. Cell survival and final ethanol concentrations were increased in the recombinant strains compared to the wild type in industrial media [Ask et al. 2013].To show a correlation between the intracellular concentration of glutathione and the resulting effect on robustness, strains accumulating different amounts of glutathione will be created. GshF is a bi-functional enzyme found in several bacterial species, that catalyzes the formation of glutathione from its precursors without accumulation of the intermediate product γ- glutamylcysteine and without any relevant feedback inhibition. GshF will be overexpressed in a CEN.PK strain, followed by deletion of the native GSH1 and GSH2 enzymes catalyzing the two-step reaction in S. cerevisiae.
19.	Bergkvist, Isabelle, et al. (författare) Skogen - en växande energikälla : sammanfattande rapport från Effektivare Skogsbränslesystem 2007-2010 2010 Rapport (övrigt vetenskapligt/konstnärligt)
20.	Anasontzis, George E, 1980, et al. (författare) Linking growth on lignocellulosic carbon sources to gene expression through secretome and transcriptome analysis in new filamentous fungi isolates from Vietnamese habitats 2013 Ingår i: Wallenberg Wood Science Center Workshop, 17-19 June, 2013, Södertälje. Konferensbidrag (övrigt vetenskapligt/konstnärligt)
21.	Muzamal, Muhammad, 1986 (författare) Steam Explosion of Wood 2014 Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract The rising price of petroleum and environmental concerns regarding CO2 emissions has increased interest in alternative renewable resources. Biomass can be considered as an excellent alternative raw material. A biorefinery uses biomass and produces fuel, energy and value-added chemicals. The biorefinery is an emerging field and requires much development to compete with already established petroleum-based industries. One of the greatest challenges to the biorefinery is that the raw material; biomass, has a complex chemical composition and physical structure. A pretreatment process is necessary to induce physico-chemical changes in the biomass and transform it into easily digestible material. The main factor limiting enzymatic digestion of biomass is accessibility to chemical constituents. Steam Explosion (SE) pretreatment is a promising process that has many potential benefits compared to the alternatives, e.g. it has less hazardous process chemicals and conditions, less environmental impact, fewer energy requirements and lower capital investment.Existing literature on the SE process mainly concerns products obtained after the process. Knowledge about the physical processes that take place during the SE pretreatment is limited. This licentiate thesis is based on experimental and modelling studies performed with the aim of gaining knowledge of the basic mechanisms of this process. The SE is a three-step process that involves; (i) treatment of wood with pressurized steam for a specific period of time, (ii) explosion of wood chips through the rapid release of pressure, and (iii) impact of softened wood chips with other chips and vessel walls. In the experimental part these steps have been carefully isolated and the effects of these steps on internal and external structures of single spruce wood pieces have been studied. The effect of vapour expansion and the creation of stresses during the explosion step on a single cell of spruce wood (with four layers; P, S1, S2 and S3) at high temperature and moisture content have been modelled using the Finite Element Method.The study reveals that all the steps of the SE process contribute to structural changes in the wood material and increase pore size which increases the accessibility of chemical reagents and enzymes. A wood piece disintegrates into smaller pieces during the impact step. The vapour expansion inside cells during the explosion step causes each cell to expand in all directions and creates high stress and strain fields perpendicular to the cell direction. In general, cell wall damage is more likely to occur in cells with thin walls, i.e. earlywood; damaged P, S1 and S3 layers; low MFAs; irregular cross-sections and sharp corners.
22.	Hermansson, Sven, et al. (författare) Testbädd Mellanskalig Biorbränsleförbränning - en förstudie 2014 Rapport (övrigt vetenskapligt/konstnärligt)abstract Conversion of biomass to heat and power plays an important role in the transition of the Swedish energy system from fossil based to renewables. For manufacturers and users of medium scale combustion plants (0.5 – approx. 15 MWth), a spectrum of challenges are accounted with both today’s and future flexible use of modern biomass fuels. Such challenges are e.g. fuel handling and processing together with combustion instabilities caused by new fuels with resulting ware-and-tear and elevated emission levels. However, the possibilities to test and try out new innovations is very limited, which is why a Test Bed has the potential to significantly contribute to the innovation growth within the sector. The purpose of this feasibility study therefore to investigate the prerequisites for the establishment of a Test Bed for Medium Scale Biomass Combustion. The fundament of the feasibility study is a survey of the existing infrastructure for testing and innovation development of medium scale biomass combustion, which could be further developed and interconnected. Furthermore, a broad inquiry has been performed among market actors, focusing on the present and future need together with existing conditions for taking part in the development of a test bed. These first two steps has then been synthesized into recommendations on how a test bed should be developed and exploited by relevant actors. The major conclusions and recommendations of the feasibility study are:  A cost efficient and innovative Test Bed system for medium scale biomass combustion could be developed by enhanced cooperation between passive test-bed like plants and systems, industrial testing plants and research activities,  Development of a test bed system is hindered by the fact that there is no clear receiver of such system on the market. Stake holder cooperation is today weak, which makes common investments and financing impossible  There is no economic support for the erection of new, dedicated test bed facilities for medium scale biomass combustion,  Pre-treatment of biomass raw material with the purpose of enhancing fuel quality simultaneously refining products from the biomass has been found to show good potential for further development of test beds. This study therefore recommends that such investigation should be taken under consideration.
23.	Adeboye, Peter, 1982, et al. (författare) Conversion of lignin-derived phenolic compounds by Saccharomyces cerevisiae 2014 Ingår i: 36th Symposium on Biotechnology for Fuels and Chemicals, April 2-May 1st, Clearwater Beach, Florids, USA. Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract Lignin breakdown during biomass pretreatment releases a wide array of phenolic compounds in lignocellulose hydrolysates. Phenolic compounds, together with organic acids and furaldehydes are known to be inhibitors of microbial fermentation, thus limiting the efficient bioconversion of lignocellulose biomass. The goal of our study is to improve S. cerevisiae tolerance to phenolic compounds from lignocellulose hydrolysates and investigate its conversion capacities. In particular, we aimed i) to establish a correlation between the phenolic compounds structure and the effect on yeast growth, and ii) to investigate the conversion/detoxification products of selected representative compounds in order to provide strain engineering strategies for enhanced phenolics conversion.First, the effect on S. cerevisiae growth of 13 different phenolic compounds commonly found in lignocellulose hydrolysates was characterized. The compounds could be grouped in three clusters, according to their effect on lag phase duration, specific growth rate and cell density. Next, coniferyl aldehyde, p-coumaric acid and ferulic acid were chosen as representative compounds and their conversion product by S. cerevisiae in aerobic culture in bioreactor were identified and followed throughout the fermentation time. Understanding the effect of different phenolics on yeast and their conversion/ detoxification pathways is the first step not only in strain engineering for enhanced robustness, but also for designing new biorefinery concepts, where the bioconversion of lignin-derived aromatics could potentially be the source of new bio-based chemicals.
24.	Bettiga, Maurizio, 1978, et al. (författare) Yeast physiology studies and metabolic engineering for enhanced robustness 2014 Ingår i: Enzitec 2014- XI Seminário Brasileiro de Tecnologia Enzimática. Barra da Tijuca-Rio de Janeiro, April 14th to 16th, 2014. Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract The extensive research on second-generation ethanol has paved the way to a new concept of bio-based industry, where lignocellulosic material is the primary source of sugars, to be converted to a number of fuels and chemicals. Sugars are released from cellulose and hemicellulose by pretreatment and hydrolysis steps. Harsh conditions during pretreatment promote the formation of a number of inhibitory compounds, among which weak organic acids, furaldehydes and phenolic compounds. In addition, the product of interest can act as a potent inhibitor. Regardless of the product, robust microorganisms are a prerequisite for the feasibility of lignocellulose-based bioprocesses.Current research carried out by our group focuses on the yeast Saccharomyces cerevisiae and aims at investigating the molecular bases of microbial robustness. Our efforts include the identification of the molecular targets of different classes of fermentation inhibitors aiming at understanding the complex responses of the cells to these compounds. The final goal is to engineer more robust strains. The concept of robustness will be discussed and examples of key features for S. cerevisiae robustness as well as examples of successful engineering to increase robustness will be presented.In particular, during this presentation, the following results will be discussed i) the study of redox and energy metabolism as key determinants of tolerance; ii) conversion routes of in S. cerevisiae as a way of detoxification from phenolic compounds; iii) cell membrane engineering as a strategy to achieve enhanced tolerance to weak acids.
25.	Modin, Oskar, 1980, et al. (författare) Opportunities for microbial electrochemistry in municipal wastewater treatment – an overview 2014 Ingår i: Water Science and Technology. - : IWA Publishing. - 1996-9732 .- 0273-1223. ; 69:7, s. 1359-1372 Tidskriftsartikel (refereegranskat)abstract Microbial bioelectrochemical systems (BESs) utilise living microorganisms to drive oxidation and reduction reactions at solid electrodes. BESs could potentially be used at municipal wastewater treatment plants (WWTPs) to recover the energy content of organic matter, to produce chemicals useful at the site, or to monitor and control biological treatment processes. In this paper, we review bioelectrochemical technologies that could be applied for municipal wastewater treatment. Sjölunda WWTP in Malmö, Sweden, is used as an example to illustrate how the different technologies potentially could be integrated in an existing treatment plant and the impact they could have on the plant’s utilization of energy and chemicals.
26.	Dimitriou, Ioannis, et al. (författare) Slow expansion and low yields of willow short rotation coppice in Sweden; implications for future strategies 2011 Ingår i: Biomass and Bioenergy. - : Elsevier BV. - 1873-2909 .- 0961-9534. ; 35:11, s. 4613-4618 Tidskriftsartikel (refereegranskat)abstract About 16 000 ha of commercial willow Short Rotation Coppice (SRC) fields for production of biomass for energy were planted in the early 1990s in Sweden. The cultivated with SRC area has remained almost stable and was slightly decreased during the last years despite the incentives and predictions for drastic increases. Similar incentives and predictions in other countries have been lately launched. The bioenergy produced in the planted SRC areas in Sweden has been lower than anticipated, partly due to the lower than expected biomass yields and the termination of some willow SRC plantations. Explanations for the low yields are depicted based on analyzing the results of a survey where 175 willow SRC growers participated. Lower biomass yields are attributed to: (i) the low input in management activities; (ii) the choice of land for the willow SRC plantation; (iii) and the level of personal involvement of the farmer. Understanding the reasons to earlier years' performance of willow SRC is important for development of better performing systems in the future, in Sweden as well as in other countries. © 2011 Elsevier Ltd.
27.	Anasontzis, George E, 1980, et al. (författare) Screening the tropical fungal biodiversity of Vietnam for biomass modifying enzymes, with secretome and transcriptome analyses 2013 Ingår i: 27th Fungal Genetics Conference. Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract In the bio-based economy concept, the current hydrocarbon fuels and non-biodegradable plastics will be replaced by new products which will derive from natural and renewable resources. The synthesis of such biofuels and biochemicals is still challenged by the difficulties to cost efficiently degrade lignocellulosic materials to fermentable sugars or to isolate the intact polymers. Biomass degrading and modifying enzymes play an integral role both in the separation of the polymers from the wood network, as well as in subsequent modifications, prior to further product development. The type of application usually defines the conditions where the reactions should take place. Thus, novel enzymes with variable combined properties, such as different thermotolerance, pH range of activity, substrate specificity and solvent tolerance, still need to be discovered and developed to achieve the highest possible efficiency in each occasion. We took advantage of the rapidly evolving and high biodiversity of the tropics and have been screening various isolates for their cellulases and hemicellulases activities. Promising strains were then cultivated in bioreactors with different carbon sources, such as wheat bran, spruce and avicel and their biomass degrading capacity was analysed through cross species protein identification of their secretome with TMT. Information on the genes involved in the different stages of the fermentation and the carbon source will be acquired with next generation sequencing of the total transcriptome. Interesting transcripts will then be used to heterologously clone and express the respective genes and identify their role in the degradation process.
28.	Gustafsson, Eva, et al. (författare) Characterization of particulate matter in the hot product gas from atmospheric fluidized bed biomass gasifiers 2011 Ingår i: Biomass and Bioenergy. - : Elsevier BV. - 0961-9534 .- 1873-2909. ; 35:Supplement 1, s. 71-78 Tidskriftsartikel (refereegranskat)abstract This study compares the characteristics of particulate matter (PM) in the hot product gas from three different atmospheric fluidized bed biomass gasifiers: a bubbling fluidized bed (BFB) gasifier, a circulating fluidized bed (CFB) gasifier, and an indirect BFB gasifier (the latter integrated with a CFB boiler). All gasifiers displayed a bimodal particle mass size distribution with a fine mode in the <0.5 μm size range and a coarse mode in the >0.5 μm size range. Compared with the mass concentration of the coarse mode the mass concentration of the fine mode was low in all gasifiers. For both the BFB and CFB gasifiers the fine-mode PM had a similar inorganic composition, indicating an origin from the ash and the magnesite bed material used in both gasifiers. In the indirect BFB gasifier the fine-mode PM was instead dominated by potassium and chlorine, and the tar fraction properties evoked tar condensation in the sampling system that affected mainly the fine-mode PM. The coarse-mode PM in the BFB gasifier was dominated by char fragments abraded from the pyrolyzed wood pellets. In the CFB gasifier the coarse-mode PM was mainly ash and magnesite bed material that passed through the process cyclone. In the indirect BFB gasifier the coarse-mode PM was mainly ash, probably originating both from the BFB gasifier and the CFB boiler.
29.	Olofsson, Martin, et al. (författare) Are algal oil yield estimations dependent on seasonal variation? 2011 Ingår i: Algae: The sustainable biomass for the future. Perspectives from the submariner project algae cooperation event Trelleborg, Sweden - September 28-29, 2011. - Berlin, Germany : s.Pro-sustainable projects GmbH. ; , s. 44-45 Konferensbidrag (populärvet., debatt m.m.)
30.	Sánchez I Nogué, Violeta, et al. (författare) Isolation and characterization of a resident tolerant Saccharomyces cerevisiae strain from a spent sulfite liquor fermentation plant 2012 Ingår i: AMB Express. - : Springer Science and Business Media LLC. - 2191-0855. ; 2:1, s. 68- Tidskriftsartikel (refereegranskat)abstract Spent Sulfite Liquor (SSL) from wood pulping facilities is a sugar rich effluent that can be used as feedstock for ethanol production. However, depending on the pulping process conditions, the release of monosaccharides also generates a range of compounds that negatively affect microbial fermentation. In the present study, we investigated whether endogenous yeasts in SSL-based ethanol plant could represent a source of Saccharomyces cerevisiae strains with a naturally acquired tolerance towards this inhibitory environment. Two isolation processes were performed, before and after the re-inoculation of the plant with a commercial baker’s yeast strain. The isolates were clustered by DNA fingerprinting and a recurrent Saccharomyces cerevisiae strain, different from the inoculated commercial baker’s yeast strain, was isolated. The strain, named TMB3720, flocculated heavily and presented high furaldehyde reductase activity. During fermentation of undiluted SSL, TMB3720 displayed a 4-fold higher ethanol production rate and 1.8-fold higher ethanol yield as compared to the commercial baker’s yeast. Another non-Saccharomyces cerevisiae species, identified as the pentose utilizing Pichia galeiformis, was also recovered in the last tanks of the process where the hexose to pentose sugar ratio and the inhibitory pressure are expected to be the lowest.
31.	Teghammar, Anna (författare) Biogas Production from Lignocelluloses : Pretreatment, Substrate Characterization, Co-digestion and Economic Evaluation 2013 Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract Biogas production from organic materials can be used as a renewable vehicle fuel, provide heat and generate electricity and can thereby reduce the greenhouse gas emissions. This thesis focuses on the biogas production based on lignocelluloses. There is an abundant availability of lignocelluloses, constituting 50% of the total biomass worldwide. However, the biomass recalcitrance limits the microbial degradation as well as the biogas production from these types of materials. In the present work different pretreatment methods have been performed in order to decrease the biomass recalcitrance and improve the biogas production. Steam explosion pretreatment, together with the addition of sodium hydroxide and hydrogen peroxide, has been performed on lignocellulosic-rich paper tube residuals. The pretreatment has resulted in methane yields of up to 493 NmL/gVS, which is an increase by 107% compared with untreated material. Furthermore, the use of an organic solvent, N-methylmorpholine-N-oxide (NMMO), was evaluated as a pretreatment method for spruce (both chips and milled), rice straw, and triticale straw. The NMMO pretreatment resulted in 202, 395, 328, and 362 NmL CH4/g carbohydrates produced of these substrates, respectively, corresponding to an increase of between 400-1,200% compared with the untreated version of the same material. Moreover, the paper tube residuals have been co-digested with an unstable nitrogen-rich substrate mixture, mainly based on municipal solid waste. The addition of the lignocellulosic-rich paper tubes in a co-digestion process showed stabilizing effects and prevented the accumulation of volatile fatty acids with a subsequent reactor failure. Additionally, synergistic effects have been found leading to between 15-33% higher methane yields when paper tubes were added to the co-digestion process compared with the yields calculated from the methane potentials of the two substrates. Substrate characterization analysis can be used to study the changes on the lignocellulosic components after the pretreatment, relating the changes to the performance in the anaerobic digestion. Increased accessible surface area, measured by the Simons’ stain and the enzymatic adsorption methods, as well as decreased crystallinity, determined by using the Fourier Transform Infrared Spectroscopy, can all be linked to improved biogas production after pretreatment. Finally, the NMMO pretreatment on forest residues has been financially evaluated for an industrial scale process design. The base case that was evaluated simulated a case where pretreated forest residues were co-digested with the organic fraction of municipal solid waste to obtain optimal nutritional balance for the anaerobic digestion. This process has been found to be economically feasible with an internal rate of return of 20.7%.
32.	Tomas-Pejo, Elia, 1980, et al. (författare) EVALUATION OF EVOLVED AND BARCODED XYLOSE FERMENTING STRAINS FOR BIOETHANOL PRODUCTION FROM LIGNOCELLULOSE 2012 Ingår i: Science and Technology Day 2012, Chalmers University of Technology, 27th March 2012. Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract Lignocellulosic raw materials for bioethanol production are today the basis for many ethanol production sites around the world. However, the utilization of engineered yeast strains for second generation ethanol production at large-scale can still be improved. Yeasts mainly use the sugars present in the lignocellulosic biomass but, toxic compounds derived from cellulose, hemicellulose and lignin degradation during pretreatment are also found in the media and inhibit yeast growth. Furthermore, wild type Saccharomyces cerevisiae is not able to ferment xylose which could constitute up to 40% of the lignocellulose material. Hence the recombinant yeast strains must be robust and ferment xylose to ethanol with high yields in the presence of inhibitors.In this study, different evolved xylose fermenting Saccharomyces cerevisiae strains have been compared in ethanol production processes from lignocellulosic hydrolysates. The differences between using single cell transformants and mixed populations will be evaluated in terms of ethanol production in large scale bioreactors.Furthermore, we have established a method to barcode the evolved yeast strains in order to be able to verify their origin. It is of outmost importance that after barcoding the original characteristics of a yeast strain are maintained. Those requirements can only be fulfilled by using a dominant selection principle. We have obtained a few hundred transformants that were shown to contain the new unique barcode DNA sequence via DNA isolation and DNA sequencing. The transformed strains must be able to grow on the lignocellulosic material and consume xylose at the same rate as before the transformation which also was tested in this study.
33.	Ma, Charlie, et al. (författare) Characterization of reactor ash deposits from pilot-scale pressurized entrained-flow gasification of woody biomass 2013 Ingår i: Energy & Fuels. - : American Chemical Society (ACS). - 0887-0624 .- 1520-5029. ; 27:11, s. 6801-6814 Tidskriftsartikel (refereegranskat)abstract Pressurized entrained-flow gasification of renewable forest residues has the potential to produce high-quality syngas suitable for the synthesis of transport fuels and chemicals. The ash transformation behavior during gasification is critical to the overall production process and necessitates a level of understanding to implement appropriate control measures. Toward this end, ash deposits were collected from inside the reactor of a pilot-scale O 2-blown pressurized entrained-flow gasifier firing stem wood, bark, and pulp mill debarking residue (PMDR) in separate campaigns. These deposits were characterized with environmental scanning electron microscopy equipped with energy-dispersive X-ray spectrometry and X-ray diffractometry. The stem wood deposit contained high levels of calcium and was comparatively insubstantial. The bark and PMDR fuels contained contaminant sand and feldspar particles that were subsequently evident in each respective deposit. The bark deposit consisted of lightly sintered ash aggregates comprising presumably a silicate melt that enveloped particles of quartz and, to a lesser degree, feldspars. Discontinuous layers likely to be composed of alkaline-earth metal silicates were found upon the aggregate peripheries. The PMDR deposit consisted of a continuous slag that contained quartz and feldspar particles dispersed within a silicate melt. Significant levels of alkaline-earth and alkali metals constituted the silicate melts of both the bark and PMDR deposits. Overall, the results suggest that fuel contaminants (i.e., quartz and feldspars) play a significant role in the slag formation process during pressurized entrained-flow gasification of these woody biomasses.
34.	Bettiga, Maurizio, 1978, et al. (författare) Robust Microorganisms and Process Strategies– The Key to Successful Lignocellulose Based Ethanol Production 2012 Ingår i: ICY 2012 - International Congress on Yeast. Madison, Wisconsin, USA. August 26-30 2012. Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract Fermentation of lignocellulose raw materials bear a lot of promises, and leave a number of challenges before it can be commercialized with good economical perspectives. The development of the process is driven towards higher gravities and better process integration in order to optimize energy input and water usage. From a microbial point of view this leads to more stressful conditions, including high inhibitor concentrations, high ethanol concentrations and poor nutritional conditions in the hydrolysates to be fermented.One way of addressing these challenges is to optimize the fermentation strategy and here a novel SSF ethanol process configuration involving feeding of substrate, enzyme and yeast will be presented. We demonstrate that this strategy ensures active metabolic state of yeast throughout the process leading to increased ethanol yield and productivity.Another strategy is to improve the microbial robustness by different strain engineering approaches. The inhibitory compounds may influence the cellular metabolism in a number of ways, including direct damage on cellular functions or by perturbations of the cellular energy and redox metabolism. During this presentation the concept of microbial robustness will be discussed and examples of strategies to the design of increased microbial robustness will be given.
35.	Bernesson, Sven, et al. (författare) Svensk spannmålsbaserad drank : Alternativa sätt att tillvarata dess ekonomiska, energi- och miljömässiga potential 2011 Rapport (övrigt vetenskapligt/konstnärligt)abstract Spannmålsdrank används huvudsakligen till utfodring. Den kan utfodras antingen i blöt form (8,5-28 % ts), eller i torr form (90 % ts). Vanligen utfodras nötkreatur och grisar med drank, men även andra djurslag inom jordbruket kan utfodras. Dranken kan även användas som biogasråvara, bränsle eller som organiskt gödselmedel. Efter jäsningen återstår spannmålens smältbara protein i dranken (primärdrank) i huvudsakligen oförändrad form, medan nästan all stärkelse gått bort. Dranken blir därför ett proteinfoder. Då även fiberpolysackarider (cellulosa och hemicellulosa) återstår i denna drank, och dessa med annan processteknik kan brytas ner till jäsbara sockerarter och jäsas till etanol, och den drank som då återstår, s.k. sekundärdrank, kan användas i liknande tillämpningar som normal (primär) drank, studeras även detta i det här projektet. En nackdel med denna teknik är att en del av aminosyrorna i drankens protein bryts ner. I de ekonomiska beräkningarna och livscykelanalyserna har det antagits att 50 % av lysinet och 20 % av metioninet brutits ner i denna sekundära drank. Arbetets syfte var att utvärdera hur spannmålsdrank kan användas i olika applikationer, samt att beräkna dess ekonomiska värde och produktionskostnader vid dessa användningar. Vidare att ta fram miljöbelastning såsom bl.a. emissioner av växthusgaser och energibehov för de olika användningarna vid produktion av etanol och drank. Dessutom att analysera betydelsen av att dranken behandlas med ytterligare en process, där en del av spannmålens cellulosa och hemicellulosa omvandlas till etanol, och sekundärdrank erhålles. Idisslare, som nötkreatur och får, kan utfodras med en stor del av proteinet i fodret som vetedrank. Protein från andra källor kan behövas för att den totala mängden protein ska bete sig på önskat sätt vid matsmältningen. Till grisar och fjäderfä kan drygt 10 %, respektive ca 10 %, av fodret bestå av vetedrank. Smågrisar är känsliga för fodrets smaklighet, och det är därför inte säkert att de alltid kan äta foder som innehåller vetedrank. Till fjäderfä kan man få begränsa inblandningen av drankprodukter i fodret om gödseln skulle bli blöt och kladdig. Till hästar kan ca 10 %, i bästa fall uppåt 20 %, av kraftfodret bestå av vetedrank om man ej drabbas av smaklighetsproblem. Spannmålsdrank kan eldas antingen blöt eller torkad beroende på eldningsutrustningen. Drank med ursprung i spannmål innehåller höga halter alkalimetaller, som ger en aska med låg smältpunkt, vilket gör att den troligen sintrar lätt. Höga halter av svavel och klor kan ge problem med korrosion. Mängden aska är ganska stor, ca 5 % av torrsubstansen. Det höga innehållet av kväve (ca 5 % av ts) gör att kväveoxidemissionerna sannolikt blir höga, och då i nivå med vad som erhållits vid eldning av rapsexpeller med ungefär samma kvävehalt, 2-3,6 gånger jämfört med kvävefattiga bränslen. Utnyttjas även en del av cellulosan och hemicellulosan för produktion av etanol (i en sekundär process), koncentreras de ämnen som ger problem vid eldningen, vilket ökar sannolikheten för problem. Dessutom blir askhalten högre, medan det totala värmevärdet minskar i takt med att cellulosa och hemicellulosa blir till etanol. Som gödselmedel innehåller drankens torrsubstans ca 5,7 % kväve, 0,8-1,5 % fosfor och 0,9- 1,9 % kalium. Beräkningar ger att sekundärdranks torrsubstans bör innehålla ca 7,4 % kväve, 1,0-2,0 % fosfor och 1,2-2,4 % kalium. Det organiskt bundna kvävet mineraliseras (frigörs) troligen långsamt såsom hos t.ex. rapsexpeller. Drank går bra att röta till biogas. Växtnäringen i rötad drank blir sannolikt mer växttillgänglig efter rötningen. Drank är ett kväverikt substrat som kan ge problem med hög halt av ammoniumkväve i biogasreaktorn. Detta gäller i högre utsträckning för sekundärdrank där näringsämnena koncentrerats då en del av cellulosan och hemicellulosan blivit till etanol. Utbytet i processen borde kunna bli 60-70 %, vid goda förhållanden kanske 80 %. Kostnadsberäkningar har gjorts där det ekonomiska värdet hos spannmålsdrank beräknats utifrån de ekonomiska värdena hos korn och sojamjöl (omsättbar energi och råprotein till nötkreatur och hästar eller lysin till grisar och fjäderfä eller metionin till fjäderfä) vid utfodring, skogsflis vid eldning (effektiva värmevärdet), kväve, fosfor och kalium vid användning som gödselmedel, samt försäljning av el och fjärrvärme från en större gårdsanläggning för biogas inklusive värdet av kväve, fosfor och kalium i rötresten vid rötning. Vid rötningen studerades fall med både 60 och 80 %:s utbyte, samt fall exklusive och inklusive rötningskostnaderna. Kostnaderna studerades för åren 2005-2010. Primärdrank fick högst värde vid användning som foder till fjäderfä (metionin) följt av: foder till hästar och nötkreatur, biogas (80 %) exkl. rötningskostnader, biogas (60 %) exkl. rötningskostnader, foder till fjäderfä (lysin) och grisar, gödselmedel, eldning för uppvärmning, biogas (80 %) inkl. rötningskostnader och sämst biogas (60 %) inkl. rötningskostnader. För sekundärdrank ändras ordningsföljden så foder till hästar och nötkreatur får högst värde följt av: foder till fjäderfä (metionin), biogas (80 %) exkl. rötningskostnader, biogas (60 %) exkl. rötningskostnader, gödselmedel, foder till fjäderfä (lysin) och grisar, biogas (80 %) inkl. rötningskostnader, eldning för uppvärmning och sämst biogas (60 %) inkl. rötningskostnader. Värdet för sekundärdrank är högre än för primärdrank vid alla användningar utom vid utfodring av grisar och fjäderfän (baserat på lysin eller metionin). Orsaken till det lägre värdet, som foder till grisar och fjäderfän, är att i sekundärprocessen för att utvinna 13 % mer etanol, bryts 50 % av lysinet och 20 % av metioninet ner. Världsmarknadspriserna på korn och sojamjöl har en stor inverkan på drankens värde, liksom utbyte m.m. från biogasanläggningen. Priserna på skogsflis och gödselmedel hade något mindre inverkan på resultatet då dessa produkter hade ett lägre värde från början. Livscykelanalyser har gjorts av produktionen av etanol med systemutvidgning, där dranken ersätter andra produkter beroende på dess användning. Följande produkter ersätts beroende av drankens användning: sojamjöl och korn vid utfodring (råprotein till nötkreatur och hästar; lysin till grisar och fjäderfä; metionin till fjäderfä); skogsflis vid eldning; konstgödsel NPK vid gödsling; vall till biogas och överskottskonstgödsel vid biogasråvara. För primärdrank blir, för global uppvärmning, ordningsföljden från lägst påverkan: fjäderfä (metionin), hästar och nötkreatur, fjäderfä och grisar (lysin), biogas (80 % och 60 %), gödselmedel och sämst eldning. Ordningsföljderna blir ungefär desamma för försurning och eutrofiering. För energiåtgång blir ordningsföljden från lägsta: biogas (80 % och 60 %), gödselmedel, eldning, fjäderfä (metionin), hästar och nötkreatur och sist fjäderfä (lysin) och grisar. För sekundärdrank blir, för global uppvärmning, ordningsföljden från lägst påverkan: hästar och nötkreatur, fjäderfä (metionin), biogas (80% och 60 %), grisar och fjäderfä (lysin), gödselmedel och sist eldning. För energiåtgång blir ordningsföljden från lägsta: biogas (80% och 60 %), hästar och nötkreatur, fjäderfä (metionin), gödselmedel, eldning, och sist grisar och fjäderfä (lysin). Produktionen av etanol och sekundärdrank ger lägst miljöbelastning då sekundärdranken blir foder till nötkreatur och hästar, samt används som biogasråvara. Vid de andra användningsområdena för dranken, ger produktionen av etanol och primärdrank lägst miljöbelastning. Energiåtgången för produktion av etanol och sekundärdrank blir, för samtliga användningsområden för dranken, högre än vid produktion av etanol och primärdrank. Orsaken till detta är att en energikrävande extra process tillkommer vid produktionen av etanol och sekundärdrank. Låter man istället biogasen, i det ovan beskrivna systemet, ersätta bensin direkt i lätta fordon, blir miljövinsten vad gäller växthusgaser större än i alla andra fall beroende på att ett fossilt bränsle ersätts direkt. Till skillnad från de andra studerade användningsområdena för dranken, blir primärdrank bättre än sekundärdrank då den har mer cellulosa och hemicellulosa kvar som kan bli till biogas. Även energivinsten visar upp ett liknande resultat som växthusgaserna. Energibalanser, som kan beskrivas som kvoten mellan utgående energi hos etanol och drank som effektivt värmevärde, och energiåtgången i alla steg för hela produktionskedjan, beräknades. Dessa innehåller alla steg från odlingen av höstvetet tills dess att det färdiga etanolbränslet är färdigt att tanka och dranken är transporterad till gården och då är färdig att utfodra. Dess värden har beräknats till 1,96 för etanol och primärdrank från en ordinär etanolprocess och 1,75 för etanol och sekundärdrank från en process som ger 13 % mer etanol från även en del av spannmålens cellulosa och hemicellulosa. Om dranken inte torkas förbättras dessa energibalanser till 2,84 respektive 2,22. Om halva arealen av vete, korn och rågvete (knappt 400 000 ha) används till etanol skulle knappt 600 000 ton primärdrank erhållas. Nuvarande djurbestånd kan konsumera ungefär två tredjedelar av denna, varav mjölkkorna en tredjedel och slaktsvinen knappt en sjättedel. Om även en del av spannmålens cellulosa och hemicellulosa används för etanolproduktion erhålls ca 470 000 ton sekundärdrank, av vilken nuvarande djurbestånd kan konsumera ca tre fjärdedelar, varav mjölkkorna knappt två femtedelar och slaktsvinen knappt en femtedel.
36.	Ask, Magnus, 1983, et al. (författare) Intracellular redox state as key target for Saccharomyces cerevisiae tolerance to lignocellulosic hydrolysate inhibitors 2013 Ingår i: 35th Symposium on Biotechnology for Fuels and Chemicals (April 29-May 2, 2013). Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract Liberation of sugars monomers from the polysaccharides constituting lignocellulosic biomass requires pretreatment and hydrolysis. Harsh conditions during pretreatment promote the formation of a number of inhibitory compounds, among which the furaldehydes furfural and hydroxymethylfurfural (HMF) have shown to impede growth and limit ethanol productivity of the yeast Saccharomyces cerevisiae. Cellular damage response to such inhibitory molecules and repair come at an energy cost for the cell, which could be reflected by alterations in energy and redox metabolism. In this study, S. cerevisiae cultures where treated with sub-lethal concentrations of furfural and HMF, both in continuous and batch cultivations. In continuous cultures, the inhibitors concentration was as close as possible to lethal, yet allowing steady state. In batch cultivations, the chosen concentration completely inhibited growth, yet allowing growth resumption. Metabolites connected to energy and redox metabolism such as NAD(P)H, NADP+, ATP, ADP and AMP were quantified and transcriptome analysis was performed. The results, along with data from thorough physiological characterisation under the studied conditions, suggested a severe impact of furfural and HMF on energy and redox metabolism. Based on this evidence, new strain with altered redox carriers intracellular concentration were engineered. The new recombinant strains showed higher ethanol productivity in the presence of lignocellulosic hydrolysate inhibitors.
37.	Wang, Ruifei, 1985, et al. (författare) Process optimization of multi-feed SSCF 2014 Ingår i: 10th European Symposium on Biochemical Engineering Sciences and 6th International Forum on Industrial Bioprocesses. Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract Economical production of bio-ethanol from lignocellulosic materials requires an efficient and robust process which enables high-solid fermentation of pretreated lignocellulose to achieve high ethanol fermentation performance. In this work, we design and optimize a high-solid fed-batch simultaneous saccharification and co-fermentation (SSCF) process with a feed of substrate, enzyme and yeast cell for efficient production of ethanol from pretreated wheat straw in both lab and pilot scale. The yeast is prepared by pre-cultivation and adaptation in a semi-continuous cultivation in liquid hydrolysate medium in order to achieve high fermentation capacity. The feeding profiles in both pre-cultivation and SSCF steps are optimized based on a previously developed multi-feed SSCF model [1] in order to maintain high activities of both hydrolytic enzyme and yeast cell resulting in highest biomass yield during pre-cultivation and highest ethanol production efficiency during SSCF process. We also demonstrate scale up of fed-batch SSCF process in a 10 m3 pilot-scale bioreactor. The fed-batch SSCF with an optimized feed of substrate, cell and enzymes reaches high ethanol fermentation performance suggesting it to be a promising process for efficient bioconversion of lignocellulosic materials to ethanol.[1] Wang et al. Bioresour. Technol., 2014
38.	Ståhlberg, Jerry (författare) Product Binding Varies Dramatically between Processive and Nonprocessive Cellulase Enzymes 2012 Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 287, s. 24807-24813 Tidskriftsartikel (refereegranskat)abstract Cellulases hydrolyze beta-1,4 glycosidic linkages in cellulose, which are among the most prevalent and stable bonds in Nature. Cellulases comprise many glycoside hydrolase families and exist as processive or nonprocessive enzymes. Product inhibition negatively impacts cellulase action, but experimental measurements of product-binding constants vary significantly, and there is little consensus on the importance of this phenomenon. To provide molecular level insights into cellulase product inhibition, we examine the impact of product binding on processive and nonprocessive cellulases by calculating the binding free energy of cellobiose to the product sites of catalytic domains of processive and nonprocessive enzymes from glycoside hydrolase families 6 and 7. The results suggest that cellobiose binds to processive cellulases much more strongly than nonprocessive cellulases. We also predict that the presence of a cellodextrin bound in the reactant site of the catalytic domain, which is present during enzymatic catalysis, has no effect on product binding in nonprocessive cellulases, whereas it significantly increases product binding to processive cellulases. This difference in product binding correlates with hydrogen bonding between the substrate-side ligand and the cellobiose product in processive cellulase tunnels and the additional stabilization from the longer tunnel-forming loops. The hydrogen bonds between the substrate-and product-side ligands are disrupted by water in nonprocessive cellulase clefts, and the lack of long tunnel-forming loops results in lower affinity of the product ligand. These findings provide new insights into the large discrepancies reported for binding constants for cellulases and suggest that product inhibition will vary significantly based on the amount of productive binding for processive cellulases on cellulose.
39.	Brandin, Jan, 1958-, et al. (författare) Selective Catalysts for Glycerol Dehydration 2013 Ingår i: CRS-2, Catalysis for Renewable Sources. - Novosibirsk, Russia : Boreskov Institute of Catalysis. - 9785990255777 ; , s. 17-18 Konferensbidrag (refereegranskat)abstract There has been an increased interest over the last decade for replacing fossil based feedstock’s with renewable ones. There are several such feedstock’s that are currently being investigated such as cellulose, lignin, hemicellulose, triglycerides etc. However, when trying to perform selective reactions an as homogeneous feedstock as possible is preferable. One such feedstock example is glycerol, a side-product from biofuels production, which is a tri-alcohol and thus has much flexibility for reactions, e.g. dehydration, hydrogenation, addition reactions etc. Glycerol in itself is a good starting point for fine chemicals production being non-toxic and available in rather large quantities [1-2]. A key reaction for glycerol valorisation is the dehydration of glycerol to form acrolein, an unsaturated C3 aldehyde, which may be used for producing acrylic acid, acrylonitrile and other important chemcial products. It has recently been shown that pore-condensation of glycerol is an issue under industrial like conditions, leading to liquid-phase reactions and speeding up the catalyst activity and selectivity loss [3]. To address this issue, modified catalyst materials have been prepared where the relevant micro and meso pores have been removed by thermal sintering; calculations have shown that pores below 45 Å may be subject to pore condensation. The catalyst starting material was a 10% WO3 by weight supported on ZrO2 in the form of beads 1–2 mm and it was thermally treated at 400°C, 500°C, 600°C, 700°C, 700°C, 800°C, 850°C, 900°C and 1000°C for 2 hours. The catalysts were characterised using nitrogen adsorption, mercury intrusion porosimetry (MIP), Raman spectroscopy and ammonia temperature programmed desorption. The thermal sintered catalysts show first of all a decreasing BET surface area with sintering commencing between 700°C and 800°C when it decreases from the initial 71 m2/g to 62 m2/g and at 1000°C there is a mere 5 m2/g of surface area left. During sintering, the micro and meso-porosity is reduced as evidenced by MIP and depicted in figure 1. As may be seen in the figure, sintering decrease the amount of pores below and around 100 Å is reduced at a sintering temperature of 800°C and above. The most suitable catalyst based on the MIP appears to be the one sintered at 850°C which is further strengthened by the Raman analysis. There is a clear shift in the tungsten structure from monoclinic to triclinic between 850°C and 900°C and it is believed that the monoclinic phase is important for activity and selectivity. Further, the heat treatment shows that there is an increase in catalyst acidity measured as mmol NH3/(m2/g) but a decrease in the acid strength as evidenced by a decrease in the desorption peak maximum temperature.
40.	Hulteberg, Christian, et al. (författare) A Process for Producing Acrolein 2012 Patent (populärvet., debatt m.m.)abstract Disclosed is a process for dehydrating glycerol into acrolein over an acidic catalyst in gas phase in the presence of hydrogen, minimizing side reactions forming carbon deposits on the catalyst.
41.	Hulteberg, Christian, et al. (författare) Method for Hydrogenating 1,2-Unsaturated Carbonylic Compounds 2011 Patent (populärvet., debatt m.m.)abstract Disclosed is a method of hydrogenating an1,2-unsaturated carbonylic compound to obtain the corresponding saturated carbonylic compound in the presence of a palladium catalyst with heterogeneous distribution of palladium
42.	Hulteberg, Christian, et al. (författare) Process for Preparing Lower Hydrocarbons from Glycerol 2011 Patent (populärvet., debatt m.m.)abstract The present invention relates to a process of preparing hydrocarbons from oxygenated hydrocarbons by use of at least two catalysts.
43.	Parsland, Charlotte, et al. (författare) Nickel-substituted Ba-hexaaluminates as catalysts stem-reforming of tars 2013 Ingår i: CRS-2, Catalysis for Renewable sources. - Novosibirsk : Boreskov Institute of Catalysis. - 9785990255777 ; , s. 62-63 Konferensbidrag (refereegranskat)abstract Gasification of woody biomass converts the solid organic material into a gaseous product with a higher energy value and by this mean provide a more carbon neutral gaseous fuel than the common fossil ones. The produced raw gas mainly contains H2, CO, CO2, CH4, H2O and N2 together with organic (tars) and inorganic (alkali) components and fine particulates. The amount of impurities in the raw gas is dependent of the fuel properties and the gasification process technology and the quality of the resulting product gas determines its suitability for more advanced purposes. One of the major general concerns within the gasification processes is the formation of tars. Tars are a vast group of polyaromatic hydrocarbons and there are a number of definitions. On an EU/IEA/US-DOE discussion meeting in Brussels 1998, a number of experts agreed on a simplified classification of tars as “all organic contaminants with a molecular weight larger than benzene” [1]. The aim of this work is to investigate the steam reforming ability of a catalytic material not previously tested in this type of application in order to achieve an energy-efficient and high-quality gasification gas. The physical demands for an optimal tar-cracking and steam reforming catalyst is a high surface area, thermal stability, mechanical strength and a capacity to withstand high gas velocities, poisons such as H2S or NH3 and other impurities. Additionally it has to resist the process steam, as steam is well known to enhance sintering of porous materials. Nickel is a familiar catalyst for steam reforming. Hexaaluminate is a well-known catalyst support with properties that may answer to the requests of a non-abrasive, high-temperaturestable and steam-resistant catalytic material. It is a structural oxide where the general formula for the doped unit cell is MIMII(x)Al12-xO19-d where MI represents the mirror plane cation and MII is the aluminum site in the lattice where substitution may occur. MII is often a transition metal ion of the same size and charge as aluminum. MI is an ion located in the mirror plane of the structure and it is a large metal ion, often from the alkaline, alkaline earth or rare earth metal group. The stability and activity of these materials are often being related to the properties of MI and MII. The activity is highly dependent on the nature of the Al-substituted metal and partially by the nature of MII [2]. In our experiments we have tested the catalytic capacity of Ni-substituted Ba-hexaaluminates synthesised by the sol-gel method [3], both in a model set-up and in a gasification plant. In the lab-scale set-up different catalyst-formulae was tested under various temperatures for reforming of methyl-naphthalene. The results show a good catalytic activity for tar-breakdown. As expected the substitution level of Ni is clearly coupled to the reaction temperature. With the most highly substituted Ni-Bahexaaluminate at 900 °C all of the methyl-naphthalene has been broken downtogether with all of the resulting hydrocarbons. The Ni-Bahexaaluminate catalyst has recently also been tested in real process-gas.These results are still to be evaluated, but indicate a positive result.
44.	Janssen, Mathias, 1973, et al. (författare) Influence of high gravity process conditions on the environmental impact of ethanol production from wheat straw 2014 Ingår i: Bioresource Technology. - : Elsevier BV. - 0960-8524 .- 1873-2976. ; 173, s. 148-158 Tidskriftsartikel (refereegranskat)abstract Biofuel production processes at high gravity are currently under development. Most of these processes however use sugars or first generation feedstocks as substrate. This paper presents the results of a life cycle assessment (LCA) of the production of bio-ethanol at high gravity conditions from a second generation feedstock, namely, wheat straw. The LCA used lab results of a set of 36 process configurations in which dry matter content, enzyme preparation and loading, and process strategy were varied. The LCA results show that higher dry matter content leads to a higher environmental impact of the ethanol production, but this can be compensated by reducing the impact of enzyme production and use, and by polyethylene glycol addition at high dry matter content. The results also show that the renewable and non-renewable energy use resulting from the different process configurations ultimately determine their environmental impact.
45.	Mayers, Joshua, 1988, et al. (författare) Influence of the N: P supply ratio on biomass productivity and time-resolved changes in elemental and bulk biochemical composition of Nannochloropsis sp. 2014 Ingår i: Bioresource Technology. - : Elsevier BV. - 0960-8524 .- 1873-2976. ; 169, s. 588-595 Tidskriftsartikel (refereegranskat)abstract This work reports for the first time the detailed impacts of dual nitrogen (N) and phosphorus (P) stress on growth dynamics and biochemical composition in the Eustigmatophyte Nannochloropsis sp. P-stress concurrent with N-stress had subtle effects on culture bulk biochemical composition, but negatively influenced biomass productivity. However, the N:P supply ratio can be raised to at least 32:1 without compromising productivity (yielding a maximum lipid content of 52% of dry weight and volumetric lipid concentration of 233mgL-1). The maximum biomass and lipid yields per unit of cell-P were 1.2kgDW (gP)-1 and 0.54kglipid (gP)-1. The P concentration of many common media is thus in surplus for optimal Nannochloropsis sp. biomass and lipid production, offering potential for significant savings in P usage and improving the sustainability of algal cultivation. © 2014 Elsevier Ltd.
46.	Skoglund, Nils, 1979-, et al. (författare) Combustion of biosolids in a bubbling fluidized bed part 1 : main ash forming elements and ash distribution with a focus on phosphorus 2014 Ingår i: Energy & Fuels. - : American Chemical Society (ACS). - 0887-0624 .- 1520-5029. ; 28:2, s. 1183-1190 Tidskriftsartikel (refereegranskat)abstract This is the first in a series of three papers describing combustion of biosolids in a 5-kW bubbling fluidized bed, the ash chemistry, and possible application of the ash produced as a fertilizing agent. This part of the study aims to clarify whether the distribution of main ash forming elements from biosolids can be changed by modifying the fuel matrix, the crystalline compounds of which can be identified in the raw materials and what role the total composition may play for which compounds are formed during combustion. The biosolids were subjected to low-temperature ashing to investigate which crystalline compounds that were present in the raw materials. Combustion experiments of two different types of biosolids were conducted in a 5-kW benchscale bubbling fluidized bed at two different bed temperatures and with two different additives. The additives were chosen to investigate whether the addition of alkali (K2CO3) and alkaline-earth metal (CaCO3) would affect the speciation of phosphorus, so the molar ratios targeted in modified fuels were P:K = 1:1 and P:K:Ca = 1:1:1, respectively. After combustion the ash fractions were collected, the ash distribution was determined and the ash fractions were analyzed with regards to elemental composition (ICP-AES and SEM-EDS) and part of the bed ash was also analyzed qualitatively using XRD. There was no evidence of zeolites in the unmodified fuels, based on low-temperature ashing. During combustion, the biosolid pellets formed large bed ash particles, ash pellets, which contained most of the total ash content (54%–95% (w/w)). This ash fraction contained most of the phosphorus found in the ash and the only phosphate that was identified was a whitlockite, Ca9(K,Mg,Fe)(PO4)7, for all fuels and fuel mixtures. With the addition of potassium, cristobalite (SiO2) could no longer be identified via X-ray diffraction (XRD) in the bed ash particles and leucite (KAlSi2O6) was formed. Most of the alkaline-earth metals calcium and magnesium were also found in the bed ash. Both the formation of aluminum-containing alkali silicates and inclusion of calcium and magnesium in bed ash could assist in preventing bed agglomeration during co-combustion of biosolids with other renewable fuels in a full-scale bubbling fluidized bed.
47.	Isaksson, Johan, 1983, et al. (författare) Pretreatment methods for gasification of biomass and Fischer-Tropsch crude production integrated with a pulp and paper mill 2014 Ingår i: Clean Technologies and Environmental Policy. - : Springer Science and Business Media LLC. - 1618-954X .- 1618-9558. ; 16:7, s. 1393-1402 Tidskriftsartikel (refereegranskat)abstract In this paper, the influence on the system performance and greenhouse gas (GHG) emissions of different biomass pretreatment methods before gasification and Fischer–Tropsch (FT) crude production was evaluated. Entrained flow gasification has the benefit of producing a practically tar-free synthesis gas with nearly complete carbon conversion. This gasifier type requires a relatively dry fuel, with small particle size, at high pressure. The size can be acquired by milling, which is energy intensive and feeding is challenging. Torrefaction of biomass facilitates milling; it thus requires less electricity, however, the torrefaction process requires heat. Pyrolysis decomposes the biomass into gaseous, liquid, and solid parts, respectively. This further makes feeding easier, but comes with a greater heat demand than torrefaction. The impact of the different pretreatment methods on the overall energy system has been evaluated using process integration methodology. The results show that the excess heat from an FT process with a biomass input of 300 MWHHV can replace the bark boiler in a large chemical pulp and paper mill, producing 350,000 tonnes of bleached paperboard annually. With the preconditions given for this study, thermal pretreatment of biomass may be beneficial in terms of wood-to-FT crude efficiency, with efficiencies up to 68 %, assuming 40 % electrical efficiency. Pretreatment using pyrolysis performed the best in regards to GHG emissions, if CO2 from acid gas removal was vented, while milling, with an annual reduction of around 700,000 tonnes of CO2,eq, had the best results if the CO2 was captured and sequestrated.
48.	Janssen, Mathias, 1973, et al. (författare) Simulation and LCA of a bioethanol process technology in development 2013 Ingår i: Proceedings of the 7th International Society for Industrial Ecology Biennial Conference. Konferensbidrag (refereegranskat)abstract The development of sustainable processes for the production of second generation biofuels is an ongoing effort. Not only does such a process need to be economically feasible, it should also produce a biofuel that has a lower environmental impact compared to first generation biofuels or fossil fuels. In this work, Life cycle assessment (LCA) is used for the evaluation of such a process along its development path. The objectives of this evaluation are to help improve and/or optimize the process in development from an environmental perspective and to help guide this development. In particular, the process under study uses high-gravity fermentation, i.e. a process with a high solids concentration in the fermentation reactor, for the production of ethanol from wood and straw. A simulation model of a plant with an industrially relevant capacity using the high-gravity technology has been set up in order to address issues of scaling up the process in development (process-level scale). Data from lab experiments are used by this model and the simulation results are subsequently used in the LCA model in order to calculate the environmental impact of the technology at an industrial scale. Furthermore, the scale at which biofuels are applied in land transport, partly due to targets set in e.g. the EU Renewable Energy Directive, needs to be accounted for (biofuel sector-level scale). The consequent feedstock use, and resulting land use and land use change impacts, as well as biogenic carbon emissions need to be included in the LCA. This paper discusses the modeling at the aforementioned process level and results are presented in order to demonstrate the importance of considering scale issues at this level. The inclusion of scale issues at the biofuel sector level in LCA will be discussed.
49.	Janssen, Mathias, 1973, et al. (författare) Use of LCA during process development: The case of a new bioethanol production process 2013 Konferensbidrag (övrigt vetenskapligt/konstnärligt)
50.	Peciulyte, Ausra, 1986, et al. (författare) Cellulolytic enzyme interaction with lignocellulose. Insight to factors limiting enzymatic hydrolysis 2013 Ingår i: Gordon Conference: Cellulosomes, Cellulases & Other Carbohydrate Modifying Enzymes internal database. Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract Liberation of fermentable soluble sugars from lignocellulosic biomass during the course of enzymatic hydrolysis is the major obstacle to large-scale implementation of biorefineries due to high cost of enzymes. Enzymatic hydrolysis of lignocellulosic biomass is often incomplete and, therefore, it is of great importance to understand the limitations of the process. Among the limitations of enzymatic hydrolysis, structural properties of lignocellulose have an effect of enzymatic hydrolysis efficiency. Currently, there is a lack of direct methods for visualization and quantification of spatial polymer distribution in lignocellulosic biomass and monitoring of interactions between cellulose degrading enzymes and the substrate. The focus of the work was (i) structural characterization of lignocellulose during the course of hydrolysis and (ii) to provide a more detailed understanding of cellulolytic enzyme interaction with lignocellulose. The overall aim was to understand the limitations in enzymatic hydrolysis of lignocellulosic biomass.Enzymatic hydrolysis was studied on industrial-like lignocellulosic and cellulosic substrates, resulting from alkaline pulping and steam explosion of spruce. Enzymatic hydrolysis of lignocellulosic substrates was compared to enzymatic hydrolysis of model cellulosic substrates. Enzymatic hydrolysis of the substrates was performed with commercial enzyme mixture Celluclast 1.5 L and also with designed enzyme mixtures, consisting of mono-component enzymes. The structural properties of the substrates during an incrementing time of hydrolysis were analyzed by solid-state Nuclear Magnetic Resonance (NMR) spectroscopy, Coherent Anti-Strokes Raman Scattering (CARS) and Second Harmonic Generation (SHG) microscopy. Hydrolysis products were verified by High Performance Anion Exchange Chromatography with Pulsed Amperometric Detection (HPAEC-PAD). Dynamics of the hydrolysis was analyzed by Quartz Crystal Microbalance with Dissipation (QCM-D) technique.

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