| 1. |
- Ahlström, Peter, et al.
(författare)
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A Survey of the Role of Thermodynamics and Transport Properties in ChE University Education in Europe and the USA
- 2010
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Ingår i: Chemical Engineering Education. - : Chemical Engineering Department, University of Florida. - 0009-2479. ; 44:1, s. 35-43
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Tidskriftsartikel (refereegranskat)abstract
- Thermodynamics and Transport Properties (TTP) is a central subject in the majority of chemical engineering curricula worldwide and it is thus of interest to know how it is taught today in various countries if chemical engineering education is to be improved. A survey of graduate thermodynamics education in the USA was performed a few years ago by Visco et al. [1] but as far as we know no systematic study of the undergraduate thermodynamics education has been performed, at least in recent years. In the present study, a survey about TTP education in Europe and the USA is presented. Results were obtained from nearly twenty different European countries and the USA and in total answers from about 150 universities were used for this study. The study is performed under the auspices of the Working Party of Thermodynamics and Transport Properties of the European Federation of Chemical Engineering. The survey was performed using a web based surveying system for which invitations were sent out to the universities by local representatives who were responsible for one or more countries each. Of the universities that answered more than 70 % offer BSc education 65 % offer MSc education and 55 % offer PhD education. Most universities offer at least two courses of thermodynamics. The following discussion is mainly based on the first two (undergraduate) courses reported. Half of these are taught to chemical engineers exclusively whereas the rest are taught with other branches of engineering, mainly mechanical and / or process engineering. In general two sets of course lengths were observed, corresponding either to a full semester of full time studies or to quarter of a semester. Most courses are centered around lectures and exercise classes with little or no laboratory work whereas home assignments are given in the vast majority (70-80 %) of the courses. The first course is mainly centered around the first and second law of thermodynamics whereas the second course is frequently more concentrated on phase equilibria. Both of these courses are mainly comprising of classical thermodynamics whereas the molecular interpretation often is touched upon. An analysis of the differences between thermodynamics education in Europe and the USA in presently being undertaken and results from this will also be presented. An investigation of the use of thermodynamics within industry is also on-going within the Working Party and results will be reported in the near future. [1] S.K.Dube, D.P. Visco, Chem. Eng. Ed., 2005, 258-263.
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| 2. |
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| 3. |
- Barta, Zsolt, et al.
(författare)
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Techno-economic evaluation of stillage treatment with anaerobic digestion in a softwood-to-ethanol process.
- 2010
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Ingår i: Biotechnology for Biofuels. - : Springer Science and Business Media LLC. - 1754-6834. ; 3
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Tidskriftsartikel (refereegranskat)abstract
- ABSTRACT: BACKGROUND: Replacing the energy-intensive evaporation of stillage by anaerobic digestion is one way of decreasing the energy demand of the lignocellulosic biomass to the ethanol process. The biogas can be upgraded and sold as transportation fuel, injected directly into the gas grid or be incinerated on-site for combined heat and power generation. A techno-economic evaluation of the spruce-to-ethanol process, based on SO2-catalysed steam pretreatment followed by simultaneous saccharification and fermentation, has been performed using the commercial flow-sheeting program Aspen Plus™. Various process configurations of anaerobic digestion of the stillage, with different combinations of co-products, have been evaluated in terms of energy efficiency and ethanol production cost versus the reference case of evaporation. RESULTS: Anaerobic digestion of the stillage showed a significantly higher overall energy efficiency (87-92%), based on the lower heating values, than the reference case (81%). Although the amount of ethanol produced was the same in all scenarios, the production cost varied between 4.00 and 5.27 Swedish kronor per litre (0.38-0.50 euro/L), including the reference case. CONCLUSIONS: Higher energy efficiency options did not necessarily result in lower ethanol production costs. Anaerobic digestion of the stillage with biogas upgrading was demonstrated to be a favourable option for both energy efficiency and ethanol production cost. The difference in the production cost of ethanol between using the whole stillage or only the liquid fraction in anaerobic digestion was negligible for the combination of co-products including upgraded biogas, electricity and district heat.
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| 4. |
- Benko, Zsuzsa, et al.
(författare)
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Heat extraction of corn fiber hemicellulose
- 2007
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Ingår i: Applied Biochemistry and Biotechnology. - : Springer Science and Business Media LLC. - 1559-0291 .- 0273-2289. ; 137, s. 253-265
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Tidskriftsartikel (refereegranskat)abstract
- Water-soluble hemicellulose was extracted from corn fiber with microwave-assisted heat treatment. The effects of treatment temperature and initial pH of the aqueous extraction media were investigated regarding hemicellulose recovery and molecular mass of the isolated polysaccharides. In treatments carried out at neutral pH (simple water extraction), it has been demonstrated that hemicellulose recovery could be increased by applying higher treatment temperatures. However, the molecular weight of isolated hemicellulose gets significantly lower. For example, 10% of the raw materials' xylan was extracted at 160 degrees C and about 30% recovery was reached at 210 degrees C. However, the molecular mass of the isolated polysaccharide at 210 degrees C (5.82 x 10(4)) was about half of that measured at 160 degrees C (1.37 x 10(5)). Reducing the pH with sulfuric acid resulted in shorter polymer chains (1.7 x 10(4)) and lower hemicellulose yields (2.2%). Application of sodium hydroxide in the treatment showed that, compared with acid, considerably higher yields (11%) with longer polysaccharide chains (1.3 x 10(5)) could be obtained.
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| 5. |
- Brumbauer, Anikó, et al.
(författare)
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Fractionation of cellulase and beta-glucosidase in a Trichoderma reesei culture liquid by use of two-phase partitioning
- 1999
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Ingår i: Bioseparation. - 1573-8272. ; 7:6, s. 287-295
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Tidskriftsartikel (refereegranskat)abstract
- An aqueous two-phase system based on the two polymers poly(ethylene glycol) and dextran has been used for the fractionation of cellulase enzymes present in culture liquid obtained by fermentation with Trichoderma reesei. The activities of beta-glucosidase and glucanases were separated to high degree by using the two-phase systems for a counter-current distribution process in nine transfer steps. While the glucanases had high affinity to the poly(ethylene glycol) rich top phase the beta-glucosidase was enriched in the dextran-containing bottom phase. Multiple counter-current distribution performed indicates the heterogeneity of beta-glucosidase activities assuming at least four isoenzyme forms. One step concentration of beta-glucosidase by using system with 46:1 phase volume ratio resulted in 16 times higher enzyme activity.
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| 6. |
- Dienes, Dora, et al.
(författare)
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Identification of a trypsin-like serine protease from Trichoderma reesei QM9414
- 2007
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Ingår i: Enzyme and Microbial Technology. - : Elsevier BV. - 0141-0229. ; 40:5, s. 1087-1094
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Tidskriftsartikel (refereegranskat)abstract
- In the present work the genetically modified Trichoderma reesei strain QM9414 was used to produce full-length Ce17B (endoglucanase I, EGI) under the control of the constitutive Aspergillus nidulans gpdA promoter in the presence of glucose. However, the full-length Ce17B enzyme was found to be truncated to lower molecular weight components in the culture broth. Truncation of recombinant proteins produced in fungi may be due to protease activity. In order to identify major sectreted proteases, protease activity was assessed in culture filtrate of the T reesei QM9414 recombinant. Zymogram analysis revealed the presence of proteolytic activity corresponding to one protein, which was subsequently purified by a combination of ion exchange and size exclusion chromatography. The protein has a molecular mass of 25 kDa, and an isoelectric point of 7.3. By matching tryptic peptide fragments analyzed by tandem mass spectrometry to fungal proteins available in databases as well as to expressed sequence tag (EST) sequences, and comparing the coded amino acids to full-length amino acid sequences, the purified protein was found to be homologous to several trypsin-like fungal serine proteases, with the highest homology to the protease P27 from Trichoderma harzianum. The purified protein was further characterized using benzoyl-arginyl-p-nitroanilide (BApNA) as substrate. It was found to have maximum activity at pH 8 and 50 degrees C, with a k(m)-value of 0.3 mM.
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| 7. |
- Dienes, Dora, et al.
(författare)
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Production of Trichoderma reesei Cel7B and its catalytic core on glucose medium and its application for the treatment of secondary fibers
- 2006
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Ingår i: Process Biochemistry. - : Elsevier BV. - 1873-3298 .- 1359-5113. ; 41:9, s. 2092-2096
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Tidskriftsartikel (refereegranskat)abstract
- Application of cellulolytic enzymes for upgrading of secondary fibers has extensively been studied during the last decades. In many cases, research has been carried out with industrial enzyme preparations which often consist of several enzyme components. The presence of various enzymes makes the determination of the role of each of them difficult in changes of pulp and paper properties. Therefore, investigations using single enzyme preparations are necessary to understand and optimize this complex process. One of the possibilities to produce individual cellulase components is repression of undesired genes. In this work, two recombinants of Trichoderma reesei strain QM9414 were used to produce intact Ce17B (endoglucanase 1, EGI) and the catalytic core of Ce17B selectively under glucose repression of other cellulases. For homologous expression in glucose medium the gpdA promoter from Aspergillus nidulans was used. Culture filtrates containing the intact Ce17B or Ce17B core were applied for secondary fiber treatment. The treatments caused improved drainage as shown by 16-17% decrease of the Schopper-Riegler (SR) values. The effects of cellulase treatment on pulp and paper properties showed that presence or absence of a cellulose-binding module (CBM) on Ce17B does not play a determinative role. (c) 2006 Elsevier Ltd. All rights reserved.
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| 8. |
- Erdei, Borbala, et al.
(författare)
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Ethanol production from mixtures of wheat straw and wheat meal
- 2010
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Ingår i: Biotechnology for Biofuels. - : Springer Science and Business Media LLC. - 1754-6834. ; 3
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Tidskriftsartikel (refereegranskat)abstract
- Background: Bioethanol can be produced from sugar-rich, starch-rich (first generation; 1G) or lignocellulosic (second generation; 2G) raw materials. Integration of 2G ethanol with 1G could facilitate the introduction of the 2G technology. The capital cost per ton of fuel produced would be diminished and better utilization of the biomass can be achieved. It would, furthermore, decrease the energy demand of 2G ethanol production and also provide both 1G and 2G plants with heat and electricity. In the current study, steam-pretreated wheat straw (SPWS) was mixed with presaccharified wheat meal (PWM) and converted to ethanol in simultaneous saccharification and fermentation (SSF). Results: Both the ethanol concentration and the ethanol yield increased with increasing amounts of PWM in mixtures with SPWS. The maximum ethanol yield (99% of the theoretical yield, based on the available C6 sugars) was obtained with a mixture of SPWS containing 2.5% water-insoluble solids (WIS) and PWM containing 2.5% WIS, resulting in an ethanol concentration of 56.5 g/L. This yield was higher than those obtained with SSF of either SPWS (68%) or PWM alone (91%). Conclusions: Mixing wheat straw with wheat meal would be beneficial for both 1G and 2G ethanol production. However, increasing the proportion of WIS as wheat straw and the possibility of consuming the xylose fraction with a pentose-fermenting yeast should be further investigated.
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| 9. |
- Sipos, Balint, et al.
(författare)
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Steam pretreatment of dry and ensiled industrial hemp for ethanol production
- 2010
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Ingår i: Biomass & Bioenergy. - : Elsevier BV. - 1873-2909 .- 0961-9534. ; 34:12, s. 1721-1731
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Tidskriftsartikel (refereegranskat)abstract
- Biomass can be converted into liquid and gaseous biofuels with good efficiency. In this study, the conversion of industrial hemp (Cannabis sativa L.), a biomass source that can be cultivated with a high biomass yield per hectare, was used. Steam pretreatment of dry and ensiled hemp was investigated prior to ethanol production. The pretreatment efficiency was evaluated in terms of sugar recovery and polysaccharide conversion in the enzymatic hydrolysis step. For both materials, impregnation with 2% SO2 followed by steam pretreatment at 210 degrees C for 5 min were found to be the optimal conditions leading to the highest overall yield of glucose. Simultaneous saccharification and fermentation experiments carried out with optimised pretreatment conditions resulted in ethanol yields of 163 g kg(-1) ensiled hemp (dry matter) (71% of the theoretical maximum) and 171 g kg(-1) dry hemp (74%), which corresponds to 206-216 l Mg-1 ethanol based on initial dry material. (C) 2010 Elsevier Ltd. All rights reserved.
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