| 1. |
- Agnihotri, Swarnima, et al.
(författare)
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A Glimpse of the World of Volatile Fatty Acids Production and Application : A review
- 2022
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Ingår i: Bioengineered. - : Informa UK Limited. - 2165-5979 .- 2165-5987. ; 13:1, s. 1249-1275
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Forskningsöversikt (refereegranskat)abstract
- Sustainable provision of chemicals and materials is undoubtedly a defining factor in guaranteeing economic, environmental, and social stability of future societies. Among the most sought-after chemical building blocks are volatile fatty acids (VFAs). VFAs such as acetic, propionic, and butyric acids have numerous industrial applications supporting from food and pharmaceuticals industries to wastewater treatment. The fact that VFAs can be produced synthetically from petrochemical derivatives and also through biological routes, for example, anaerobic digestion of organic mixed waste highlights their provision flexibility and sustainability. In this regard, this review presents a detailed overview of the applications associated with petrochemically and biologically generated VFAs, individually or in mixture, in industrial and laboratory scale, conventional and novel applications.
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| 2. |
- Agnihotri, Swarnima, et al.
(författare)
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Ethanol organosolv pretreatment of softwood (Picea abies) and sugarcane bagasse for biofuel and biorefinery applications
- 2015
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Ingår i: Wood Science and Technology. - : Springer Science and Business Media LLC. - 0043-7719 .- 1432-5225. ; 49:5, s. 881-896
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Tidskriftsartikel (refereegranskat)abstract
- Ethanol derived from biomass has the potential to be a renewable transportation fuel that can replace gasoline. This work was carried out to establish an optimized ethanol organosolv pretreatment of Norway spruce (Picea abies) for bioethanol production (63 wt% EtOH, pH ~3.5 in aqueous phase, 170–240 °C, 90 min) utilizing hydrolytic enzymes in the saccharification step. To test the generality of the method, a series of ethanol organosolv pretreatments were also performed on sugarcane bagasse (50 wt% EtOH, pH ~3.5 in aqueous phase, 155–210 °C, 90–120 min). The degree of delignification increased with increasing temperature during pretreatment, and the fastest increase was observed with sugarcane bagasse. The pretreatments were carried out in a batch mode. The maximum degree of delignification of ~65 % was reached at ~235 °C for Norway spruce, while sugarcane bagasse reached ~80 % at ~210 °C. Cellulose was subjected to degradation (5–10 % points) at these temperatures. Subsequent enzymatic hydrolysis (30 FPU/g cellulose, 32 pNPGU/g cellulose, 50 °C, 48 h) of ethanol organosolv-pretreated biomass achieved complete conversion for both raw materials at the highest degrees of delignification.
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| 3. |
- Ferreira, Jorge, et al.
(författare)
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A review of integration strategies of lignocelluloses and other wastes in 1st generation bioethanol processes
- 2018
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Ingår i: Process Biochemistry. - : Elsevier Ltd. - 1359-5113 .- 1873-3298. ; 75, s. 173-186
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Tidskriftsartikel (refereegranskat)abstract
- First-generation ethanol plants offer successful, commercial-scale bioprocesses that can, at least partially, replace fossil fuels. They can act as platforms to integrate lignocelluloses, wastes and residuals when establishing 2nd generation ethanol. The present review gathers recent insights on the integration of intrinsic and extrinsic substrates into lot generation ethanol plants, through microbial conversion or cogeneration systems. It shows that, among different lot generation ethanol plants, sugar-based ethanol by-products, dominate integration studies characterized by strong techno-economic and life-cycle assessment components. In comparison, there are fewer studies that focus on grain-derived lignocellulosic residuals and other wastes. There is consensus that integrating second generation feedstocks into first generation plants can have positive techno-economic and environmental impacts. In addition to realizing production of ethanol from 2nd generation feedstocks, these possibilities can impact waste management by establishing relevant biorefineries and circular economy. They can also supply a wide range of renewable products. Considering the potential of this waste management strategy, further research on these and many other substrates is needed. This will shed light on the effect of the integration, the relevant types of microorganisms and pretreatments, and of other physical parameters on the effectiveness of running lot generation plants with integrated second generation feedstocks.
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| 4. |
- Karimi, Sajjad, et al.
(författare)
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Evaluating three fungal biomasses grown on diluted thin stillage as potential fish feed ingredients
- 2023
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Ingår i: Bioresource Technology Reports. - 2589-014X. ; 24
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Tidskriftsartikel (refereegranskat)abstract
- Thin stillage holds promise as a substrate for cultivating filamentous fungi. The suspended solids content of thin stillage directly influences biomass production. However, little attention has been given to its effects on fungal cultivation and composition, which is the focus of the current study. Various thin stillage dilutions were used to cultivate Zygomycete and Ascomycetes. Biomass and nutrient uptake were monitored during the cultivation. The harvested biomass was analyzed to assess nutrient composition in relation to fish dietary requirements. Thin stillage diluted to 75 % significantly enhanced fungal biomass production, with increases of 160 %, 213 %, and 235 % for A. oryzae, R. delemar, and N. intermedia, respectively. The harvested fungal biomass boasted approximately 50 % protein content, constituting 45 % essential amino acids. These findings underscore the potential of cultivating fungi in diluted thin stillage to boost biomass production and its high-quality nutritional composition positions it as a valuable candidate for fish feed formulations.
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| 5. |
- Mahboubi, Amir, et al.
(författare)
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Waste-derived volatile fatty acids for sustainable ruminant feed supplementation
- 2022
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Ingår i: Biomass, Biofuels, Biochemicals. - : Elsevier. - 9780323885119 ; , s. 407-430
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Bokkapitel (refereegranskat)abstract
- Linear livestock production practice gives rise to a number of environmental, economic, and social issues including unsustainable feed provision, resource inefficiency, and climate impacts. Provision of dietary supplements in ruminants through bioconversion of organic waste/residues is a promising way to introduce the concept of circular bioeconomy to animal feed production. Volatile fatty acids (VFAs) are natural metabolites mainly generated from the bioconversion of fiber in the rumen of ruminants, and are used as an animal's energy source and precursor for the production of animal products. Considering that VFAs can also be produced from anaerobic digestion (AD) of different organic wastes, this chapter discusses the potentials applications of waste-derived VFAs such as acetic, butyric, and propionic acids as animal feed supplementation. In this regard, first, the effect of VFAs on energy provision, dry matter intake, weight gain, weaning age, ketosis and acidosis, milk yield and composition, hormones, gastrointestinal development, etc., in ruminants are analyzed. Then the potentials of different organic waste sources for the production of VFAs through AD are presented. Finally, the purification and concentration methods such as distillation and membrane separation, whichcan be applied for the production of animal feed grade VFAs solutions, are thoroughly reviewed.
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| 6. |
- Parchami, Mohsen, et al.
(författare)
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Aqueous ethanol organosolv process for the valorization of Brewer’s spent grain (BSG)
- 2022
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Ingår i: Bioresource Technology. - : Elsevier. - 0960-8524 .- 1873-2976. ; 362
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Tidskriftsartikel (refereegranskat)abstract
- Brewers spent grain (BSG), the main solid byproduct of brewing, is annually generated by ca 37 million tons worldwide, which due to limited application, mostly ends up in landfills. This study aims to separate BSG’s fractions (lignin, cellulose, and hemicellulose) by ethanol organosolv pretreatment. Lignin-rich fractions were recovered using a two-step separation technique. The effects of temperature, retention time, and ethanol concentration on the quantity and quality of fractions were studied. The temperature considerably impacted the quality and quantity of obtained fractions, while other parameter effects greatly depended on the temperature. Substantial hemicellulose removal (90 %) along with lignin removal (56 %) and recovery (57 %) were obtained at 180 °C. The highest lignin purity (95 %) was obtained at the pretreatment conditions of 180 °C, 120 min, and 50 % ethanol concentration. This work provides an alternative route for BSG utilization, mitigating its environmental impact while enhancing the economy of a brewery.
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| 7. |
- Parchami, Mohsen, et al.
(författare)
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Biovalorization of brewer's spent grain as single-cell protein through coupling organosolv pretreatment and fungal cultivation
- 2023
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Ingår i: Waste Management. - 0956-053X .- 1879-2456. ; 169, s. 382-391
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Tidskriftsartikel (refereegranskat)abstract
- Brewer's spent grain (BSG) is a clean byproduct from the food sector, comprising 85% of the brewing process solid byproducts. BSG is mainly used as low-quality animal feed and often ends up in landfills due to its short shelf life. However, considering its abundant availability and high nutritional content, BSG holds the potential for biorefineries to produce valuable products. The recalcitrant nature of BSG poses a challenge, requiring pretreatment steps. Therefore, this study focused on valorizing BSG obtained from organosolv pretreatment by producing food- and feed-grade single-cell protein (SCP). The BSG was subject to organosolv pretreatment at 180C for 2 h with 50% v/v ethanol as solvent. Filamentous fungi N. intermedia and A. oryzae were cultivated on as-received and different fractions of organosolv-treated BSG to evaluate the effect of factors such as pretreatment, fungal strain, pretreated fraction content, and substrate loading on fungal biomass yield, biomass composition (protein content), and metabolite production. A. oryzae cultivation on all tested substrates yielded 7%-40% more biomass than N. intermedia. Cultivating A. oryzae on organosolv liquor resulted in the highest biomass protein content (44.8% ± 0.7%) with a fungal biomass concentration of 5.1 g/L. A three-fold increase in the substrate loading increased the ethanol-to-substrate yield by 50%, while protein content was decreased by 23%. Finally, a biorefinery concept was proposed to integrate the organosolv pretreatment of BSG with fungal cultivation for maximum yield of SCP while obtaining other products such as lignin and ethanol, providing a sustainable rout for managing BSG.
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| 8. |
- Rousta, Neda, et al.
(författare)
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Filamentous Fungus Aspergillus oryzae for Food : From Submerged Cultivation to Fungal Burgers and Their Sensory Evaluation – A Pilot Study
- 2021
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Ingår i: Foods. - : MDPI AG. - 2304-8158. ; 10:11
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Tidskriftsartikel (refereegranskat)abstract
- New food sources are explored to provide food security in sustainable ways. The submerged fermentation of edible filamentous fungi is a promising strategy to provide nutritious and affordable food that is expected to have a low environmental impact. The aim of the current study was to assess the novel use of Aspergillus oryzae cultivated in submerged fermentation on oat flour as a source for food products that do not undergo secondary fermentation or significant downstream processing. The fungus was cultivated in a pilot-scale airlift bioreactor, and the biomass concentration and protein content of the biomass were assessed. A tasting with an untrained panel assessed consumer preferences regarding the taste and texture of minimally processed vegetarian and vegan burger patties made from the biomass, and how the patties fared against established meat-alternative-based patties. The cultivation of Aspergillus oryzae resulted in a yield of 6 g/L dry biomass with a protein content of 37% on a dry weight basis. The taste and texture of the minimally processed fungal burger patties were to the liking of some participants. This was also reflected in diverse feedback provided by the participants. The cultivation of the fungus on oat flour and its utilization in developing burger patties shows its promising potential for the production of nutritious food. The applications of the fungus can be further developed by exploring other favorable ways to texture and season this relatively new functional food source to the preferences of consumers.
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| 9. |
- Rousta, Neda, et al.
(författare)
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Production of fungal biomass from oat flour for the use as a nutritious food source
- 2022
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Ingår i: NFS Journal. - : Elsevier BV. - 2352-3646. ; 29, s. 8-15
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Tidskriftsartikel (refereegranskat)abstract
- Fermentation can be a powerful tool for developing new sustainable foods with increased nutritional value and fermented microbial biomass derived from filamentous fungi is a promising example. This study investigates the nutritional profile of edible Aspergillus oryzae biomass produced under submerged fermentation (SmF) using oat flour as a substrate. The fermentation occurred in a 1m3 airlift bioreactor during 48 h at 35 °C and the nutritional profile of the produced fungal biomass in terms of amino acids, fatty acids, minerals (Fe, Zn, Cu, Mn), vitamins (E, D2), and dietary fiber was compared to oat flour as well as pure fungal biomass grown on semi-synthetic medium. The total amount of amino acids increased from 11% per dry weight (dw) in oat flour to 23.5% dw in oat fungal biomass with an improved relative ratio of essential amino acids (0.37 to 0.42). An increase in dietary fibers, minerals (Fe, Zn, Cu), vitamin E, as well as vitamin D2 were also obtained in the oat fungal biomass compared to oat flour. Moreover, the short chain omega-3 α-linolenic acid (ALA) and omega-6 linoleic acid (LA) values increased from 0.6 to 8.4 and 21.7 to 68.4 (mg/g dry weight sample), respectively, in oat fungal biomass. The results indicate that fungal biomass grown on oat flour could have a potential application in the food industry as a nutritious source for a wide variety of products.
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| 10. |
- Sárvári Horváth, Ilona, et al.
(författare)
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Utilization of Straw Pellets and Briquettes as Co-Substrates at Biogas Plants
- 2017
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Biogas reactors can be utilized more efficiently when straw and food waste are digested together instead of separately. In the present study, straw in the form of pellets and briquettes has been used in experiments and calculations. Co-digestion of different substrates can give a more optimal substrate composition and a more efficient utilization of available digester volume. The pelleting and briquetting process has been shown to be an adequate pretreatment method of the straw. Digesting food waste and straw together showed synergistic effects with improved degradation of the food waste as well as a higher total volumetric methane production as compared to when food waste was used as the sole substrate. Energy produced through increased biogas production was higher than the energy needed for the pelleting and briquetting process. The positive effect in regard to gas production was mainly seen for the straw pellets, results supported by both chemical and microbiological analysis. These effects were observed in both mesophilic and thermophilic conditions. In conclusion, this study illustrates that straw is a suitable co-digestion substrate to food waste and can be used to improve gas yields as well as for more efficient utilization of the digester volume. These results show the biogas potential of straw, today not yet used as a substrate to a large extent.
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| 11. |
- Yangin-Gomec, Cigdem, et al.
(författare)
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Assessment of Microbial Diversity during Thermophilic Anaerobic Co-Digestion for an Effective Valorization of Food Waste and Wheat Straw
- 2023
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Ingår i: Energies. - : MDPI. - 1996-1073. ; 16:1
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Tidskriftsartikel (refereegranskat)abstract
- In this study, predominant bacterial and archaeal populations and their roles during anaerobic mono-digestion of food waste (FW) and co-digestion of FW with straw pellets (SP) at thermophilic temperature (53 ± 1 °C) were assessed by Next Generation Sequencing (NGS) analysis at organic loading rates (OLRs) of 3.0 and 7.0 gVS/L/d. Depending on the seed; results revealed that Firmicutes, Bacteroidetes, and Proteobacteria were, respectively the most prevalent bacterial phyla at both OLRs investigated. On the other hand, Euryarchaeota was dominated by methanogens playing crucial role in biogas production and correlated mainly with the activities of Methanobacteria and Methanomicrobia at class level. Acetoclastic Methanosaetae was the predominant genus at OLR = 3.0 gVS/L/d; however, shared the same predominance with hydrogenotrophic methanogens Methanospirillium at the highest OLR. Although no clear effect in response to straw addition at OLR of 3.0 gVS/L/d could be seen in terms of methanogenic archaea at genus level, hydrogenotrophic methanogens revealed some shift from Methanobacterium to Methanospirillium at higher OLR. Nevertheless, no prominent microbial shift in the presence of wheat straw at increased OLR was likely due to adapted inoculation at start-up which was also demonstrated by relatively stable biogas yields during co-digestion.
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