| 1. |
- Momayez, Forough, et al.
(författare)
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Efficient hydrolysis and ethanol production from rice straw by pretreatment with organic acids and effluent of biogas plant
- 2017
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Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 7:80, s. 50537-50545
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Tidskriftsartikel (refereegranskat)abstract
- The effluent of biogas production plant was used for the pretreatment of rice straw for the improvement of ethanol production. In addition, the organic active ingredients of the effluent, i.e., acetic, butyric, lactic and propionic acids (1-4%), as well as water were employed for the pretreatment at 100 and 140 °C. The results indicated that pretreatment at 100 °C had no significant effect on the performance of subsequent enzymatic hydrolysis and ethanol production by simultaneous saccharification and fermentation (SSF). Among different types of organic acids presented in the effluent, lactic acid showed a better performance. The highest concentration of glucose and ethanol were achieved after 72 h enzymatic hydrolysis and SSF from the straw pretreated at 140 °C with 4% lactic acid. Applying the effluent for the straw pretreatment at 140 °C resulted in an increase in glucose and ethanol concentrations by 42.4 and 47.5%, respectively, compared to those from untreated samples. SEM, FTIR, BET, BJH, and compositional analyses were used to characterize the changes in the structure and composition of rice straw by the pretreatment. Changes in the straw swelling, cellulose crystallinity, pore size distribution, and composition were responsible for the acquired improvements.
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| 2. |
- Abedinifar, S., et al.
(författare)
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Ethanol production by Mucor indicus and Rhizopus oryzae from rice straw by separate hydrolysis and fermentation
- 2009
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Ingår i: Biomass and Bioenergy. - : Elsevier BV. - 0961-9534 .- 1873-2909. ; 33:5, s. 828-833
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Tidskriftsartikel (refereegranskat)abstract
- Rice straw was successfully converted to ethanol by separate enzymatic hydrolysis and fermentation by Mucor indicus, Rhizopus oryzae, and Saccharomyces cerevisiae. The hydrolysis temperature and pH of commercial cellulase and β-glucosidase enzymes were first investigated and their best performance obtained at 45 °C and pH 5.0. The pretreatment of the straw with dilute-acid hydrolysis resulted in 0.72 g g-1 sugar yield during 48 h enzymatic hydrolysis, which was higher than steam-pretreated (0.60 g g-1) and untreated straw (0.46 g g-1). Furthermore, increasing the concentration of the dilute-acid pretreated straw from 20 to 50 and 100 g L-1 resulted in 13% and 16% lower sugar yield, respectively. Anaerobic cultivation of the hydrolyzates with M. indicus resulted in 0.36-0.43 g g-1 ethanol, 0.11-0.17 g g-1 biomass, and 0.04-0.06 g g-1 glycerol, which is comparable with the corresponding yields by S. cerevisiae (0.37-0.45 g g-1 ethanol, 0.04-0.10 g g-1 biomass and 0.05-0.07 glycerol). These two fungi produced no other major metabolite from the straw and completed the cultivation in less than 25 h. However, R. oryzae produced lactic acid as the major by-product with yield of 0.05-0.09 g g-1. This fungus had ethanol, biomass and glycerol yields of 0.33-0.41, 0.06-0.12, and 0.03-0.04 g g-1, respectively.
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| 3. |
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| 4. |
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| 5. |
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| 6. |
- Cabrera-Rodríquez, Emir, et al.
(författare)
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Effect of sodium hydroxide pretreatment at low temperature on chemical composition and enzymatic hydrolysis of spruce
- 2013
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Ingår i: Revista CENIC Ciencias Químicas. - : Centro Nacional de Investigaciones Cientificas. - 2221-2442. ; 43:1, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- The availability of fermentable sugars is a limiting factor for large-scale production of biological products such as bioethanol. Therefore, processes to produce sugars are being developed from lignocellulosic materials by enzymatic hydrolysis. However, the cellulose fraction are not readily accessible for the hydrolyzing enzymes and an efficient hydrolysis requires pretreatment. Several processes have been investigated for this pretreatment. Pretreatment of lignocelluloses with NaOH is among the promissing methods. In the present work, the effect of NaOH pretreatment at low temperature on chemical composition and subsequent enzymatic hydrolysis of spruce was investigated. A native spruce specie obtained from the forest around Borås city in Sweden was used in an the experiments. This wood was analyzed for carbohydrate and lignin fractions according to NREL methods. The wood was chemically pretreated using 7 % (w/w) sodium hydroxide solution with 5 % (w/v) solid content at 0 °C for 0.5, 1, 2 and 3 h. Commercial enzymes, cellulase (Celluclast 1.5 L, Novozyme, Denmark) and β-glucosidase (Novozyme 188, Novozyme, Denmark) were used in the enzymatic hydrolysis with activities of 30 FPU and 50 IU per gram of wood, respectively. The pretreatments changed the material composition. It was a very low loss of carbohydrate, about 98 % recovery, suggesting no significant carbohydrate hydrolysis. Xylans were the most affected by the pretreatments. The largest xylan removal was almost 50 %, using sodium hydroxide solution for 3 h. The profile of released sugars were also analyzed and compared. An improvement of enzymatic hydrolysis yield was observed as a result of the applied pretreatments, near 40 % glucose yield could be achieved.
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| 7. |
- Carrillo Nieves, Danay, et al.
(författare)
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Improvement of biogas production from oil palm empty fruit bunches (OPEFB)
- 2011
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Ingår i: Industrial crops and products (Print). - : Elsevier BV. - 0926-6690 .- 1872-633X. ; 34:1, s. 1097-1101
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Tidskriftsartikel (refereegranskat)abstract
- Oil palm empty fruit bunches (OPEFB), a waste lignocellulosic material, which is the main byproduct of vegetable oil production industries in Indonesia and Malaysia, was utilized as a source for biogas production. Pretreatments using NaOH as well as phosphoric acid were investigated to improve the biogas production. Clear positive effects of the pretreatments on the yield of methane were observed. The best improvement was achieved when 8% NaOH for 60 min was used for the pretreatment, which resulted in 100% improvement in the yield of methane production. In addition, treatment with phosphoric acid resulted in 40% improvement in the methane yield compared with that of the untreated material. The results showed that the carbohydrate content of OPEFB could be efficiently converted to methane under the anaerobic digestion process. 97% of the theoretical value of methane production was achieved after the pretreatment with NaOH for 60 min. Moreover, the initial rate of methane production was also increased by more than 85% after the treatment with NaOH compared with that of the untreated OPEFB.
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| 8. |
- Christia, Abdi, 1991, et al.
(författare)
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Ethanol production from alkali-pretreated oil palm empty fruit bunch by simultaneous saccharification and fermentation with mucor indicus
- 2016
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Ingår i: International Journal of Green Energy. - : Informa UK Limited. - 1543-5075 .- 1543-5083. ; 13:6, s. 566-572
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Tidskriftsartikel (refereegranskat)abstract
- Oil palm empty fruit bunch (OPEFB) is a potential raw material for production of lignocellulosic bioethanol. The OPEFB was pretreated with 8% sodium hydroxide (NaOH) solution at 100°C for 10 to 90 min. Enzymatic digestion was carried out using cellulase and β-glucosidase at 45°C for 24 h. It was then inoculated with Mucor indicus spores suspension and fermented under anaerobic conditions at 37°C for 96 h. Sodium hydroxide pretreatment effectively removed 51–57% of lignin in the OPEFB and also its hemicellulose (40–84%). The highest glucan digestibility (0.75 g/g theoretical glucose) was achieved in 40-min NaOH pretreatment. Fermentation by M. indicus resulted in 68.4% of the theoretical ethanol yield, while glycerol (16.2–83.2 mg/g), succinic acid (0–0.4 mg/g), and acetic acid (0–0.9 mg/g) were its by-products. According to these results, 11.75 million tons of dry OPEFB in Indonesia can be converted into 1.5 billion liters of ethanol per year.
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| 9. |
- Ebrahimian, Farinaz, et al.
(författare)
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A biorefinery platform to valorize organic fraction of municipal solid waste to biofuels : An early environmental sustainability guidance based on life cycle assessment
- 2023
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Ingår i: Energy Conversion and Management. - : Elsevier. - 0196-8904 .- 1879-2227. ; 283
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Tidskriftsartikel (refereegranskat)abstract
- The biorefining of biowastes, specifically the organic fraction of municipal solid waste (OFMSW), into biofuels and high-value products is an energy-demanding process, still immature, and largely dependent on the process configuration and efficiency of employed microorganisms. Such issues might undermine the environmental sustainability of the biorefinery by inducing adverse impacts on human health, ecosystem quality, climate change, and resources, which need to be explored before the process scale-up. Hence, this study was performed as early sustainability guidance to investigate the environmental impacts of different biorefinery platforms for biofuels production from OFMSW. More specifically, three pretreatment methods (i.e., acetone organosolv, acid, and hot water), two hydrolysis treatments (i.e., acidic and enzymatic), and two fermentation alternatives (i.e., ethanolic fermentation and acetone-butanol-ethanol (ABE) fermentation) were investigated. Based on European Commission's Joint Research Center instruction, the environmental impacts were studied using consequential life cycle assessment for the macro-level decision context. The results demonstrated that ABE fermentation scenarios were not environmentally favorable because the avoided impacts from final products were not sig-nificant enough to compensate for the induced environmental burdens from acetone pretreatment. On the contrary, the ethanolic fermentation scenarios with either acid or hot water pretreatment outperformed both ABE fermentation and ethanolic fermentation with acetone pretreatment. Based on the results, the scenario including simultaneous dilute acid pretreatment and hydrolysis of OFMSW followed by ethanolic fermentation manifested the best performance in all damage categories, as compared to those including acetone pretreatment or higher consumption of enzymes. Such improvements in this scenario led to the highest net saving of-842 potentially disappeared fraction (PDF)/m2/yr,-249.95 kg CO2 eq, and-3275.22 MJ primary per ton of OFMSW on ecosystem quality, climate change, and resources, respectively, and the lowest net burden of 1.54 x 10-5 disability-adjusted life years (DALY) per ton of OFMSW on human health. The results of sensitivity analysis on this scenario demonstrated that the substitution of excess heat for marginal heat with fossil origin can consid-erably decrease impacts on human health.
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| 10. |
- Ebrahimian, Farinaz, et al.
(författare)
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A critical review on pretreatment and detoxification techniques required for biofuel production from the organic fraction of municipal solid waste
- 2023
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Ingår i: Bioresource Technology. - : Elsevier. - 0960-8524 .- 1873-2976. ; 368
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Tidskriftsartikel (refereegranskat)abstract
- The organic fraction of municipal solid waste (OFMSW) is a widely-available promising feedstock for biofuel production. However, the presence of different inhibitors originating from fruit and food/beverage wastes as well as recalcitrant lignocellulosic fractions hampers its bioconversion. This necessitates a pretreatment to augment the biodigestibility and fermentability of OFMSW. Hence, this review aims to provide the in-vogue inhibitory compound removal and pretreatment techniques that have been employed for efficient OFMSW conversion into biofuels, i.e., hydrogen, biogas, ethanol, and butanol. The techniques are compared concerning their mode of action, chemical and energy consumption, inhibitor formation and removal, economic feasibility, and environmental sustainability. This critique also reviews the existing knowledge gap and future perspectives for efficient OFMSW valorization. The insights provided pave the way toward developing energy-resilient cities while addressing environmental crises related to generating OFMSW.
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| 11. |
- Garcia, Ariel, et al.
(författare)
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Chemical and physical characterization and acid hydrolysis of a mixture of Jatropha curcas shells and husks
- 2015
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Ingår i: Cellulose Chemistry and Technology. - : Editura Academiei Romane,Publishing House of the Romanian Academy. - 0576-9787. ; 49:9-10, s. 737-744
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Tidskriftsartikel (refereegranskat)abstract
- Jatropha curcas L. is a tropical plant with considerable potential for producing biodiesel and other products of high economic and social interest. During the biodiesel production process from J. curcas different residues, such as shells and husks are generated. In this work, the physical characterization of J. curcas fruits was performed, and the chemical composition of a mixture of shells and husks was determined. The physical characterization revealed that shells and husks account, respectively, for 25.0 and 27.8% of the fruit weight. The compositional analyses of the material showed a rather high content of glucans (32.8% w/w) and xylans (16.4% w/w), which indicates the potential of J. curcas shells and husks for production of ethanol, xylitol and other glucose- and xylose-derived products. Acid hydrolysis was applied to a mixture of shells and husks under different sulphuric acid concentrations (from 0.5 to 4.5%), temperatures (170 – 220ºC) and time (10 – 20 min), and the hydrolytic conversion of xylan was evaluated. A zone of experimental conditions giving maximal xylan conversion was identified at around 4% H2SO4, 180ºC and reaction time below 10 min.
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| 12. |
- Garcia, Ariel, et al.
(författare)
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Chemical and physical characterization and acid hydrolysis of a mixture of Jatropha Curcas shells and husks
- 2015
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Ingår i: Cellulose Chemistry and Technology. - 0576-9787. ; 49:9-10, s. 737-744
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Tidskriftsartikel (refereegranskat)abstract
- Jatropha curcas L. is a tropical plant with considerable potential for producing biodiesel and other products of high economic and social interest. During the biodiesel production process from J. curcas different residues, such as shells and husks are generated. In this work, the physical characterization of J. curcas fruits was performed, and the chemical composition of a mixture of shells and husks was determined. The physical characterization revealed that shells and husks account, respectively, for 25.0 and 27.8% of the fruit weight. The compositional analyses of the material showed a quite high content of glucans (32.8% w/w) and xylans (16.4% w/w), which indicates the potential of J. curcas shells and husks for production of ethanol, xylitol and other glucose- and xylose-derived products. Acid hydrolysis was applied to a mixture of shells and husks under different sulphuric acid concentrations (from 0.5 to 4.5%), temperatures (170-220 degrees C) and time (10-20 min), and the hydrolytic conversion of xylan was evaluated. A zone of experimental conditions giving maximal xylan conversion was identified at around 4% H2SO4, 180 degrees C and reaction time below 10 min.
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| 13. |
- Goshadrou, Amir, et al.
(författare)
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Bioethanol production from sweet sorghum bagasse by Mucor hiemalis
- 2011
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Ingår i: Industrial crops and products (Print). - : Elsevier. - 0926-6690 .- 1872-633X. ; 34:1, s. 1219-1225
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Tidskriftsartikel (refereegranskat)abstract
- The present work deals with production of ethanol from sweet sorghum bagasse by a zygomycetes fungus Mucor hiemalis. The bagasse was treated with phosphoric acid and sodium hydroxide, with or without ultrasonication, prior to enzymatic hydrolysis by commercial cellulase and β-glucosidase enzymes. The phosphoric acid pretreatment was performed at 50 °C for 30 min, while the alkali treatment performed with 12% NaOH at 0 °C for 3 h. The pretreatments resulted in improving the subsequent enzymatic hydrolysis to 79–92% of the theoretical yield. The best hydrolysis performance was obtained after pretreatment by NaOH assisted with ultrasonication. The fungus showed promising results in fermentation of the hydrolyzates. In the best case, the hydrolyzate of NaOH-ultrasound pretreated bagasse followed by 24 h fermentation resulted in about 81% of the corresponding theoretical ethanol yield. Furthermore, the highest volumetric ethanol productivity was observed in the hydrolyzates of NaOH pretreated bagasse, especially after ultrasonication in pretreatment stage.
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| 14. |
- Goshadrou, Amir, et al.
(författare)
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Ethanol and biogas production from birch by NMMO pretreatment
- 2013
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Ingår i: Biomass and Bioenergy. - : Pergamon. - 0961-9534 .- 1873-2909. ; 49, s. 95-101
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Tidskriftsartikel (refereegranskat)abstract
- Birch wood was pretreated with N-methylmorpholine-N-oxide (NMMO or NMO) followed by enzymatic hydrolysis and fermentation to ethanol or digestion to biogas. The pretreatments were carried out with NMMO (wNMMO ¼ 85%) at 130 C for 3 h, and the effects of drying after the pretreatment were investigated. Enzymatic hydrolysis of the untreated wood resulted in 8%e10% of theoretical glucose yield after 4 days hydrolysis, while the NMMO pretreatment improved this yield to 91%. Consequently, ethanol production yield from NMMO-pretreated materials resulted in around 9-fold improvement compared to the untreated wood. On the other hand, drying of the pretreated wood had a negative impact and decreased the yield of enzymatic hydrolysis by 4%e10%. Digestion of the untreated wood with thermophilic bacteria resulted in maximum methane yield of 158 cm3 g 1 of VS in 30 days, while the NMMO pretreatment improved the methane yield up to 232 cm3 g 1 of VS (80% of the theoretical biogas yield) in just 9 days.
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| 15. |
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| 16. |
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| 17. |
- Hashemi, Seyed Sajad, et al.
(författare)
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Valorization of vinasse and whey to protein and biogas through an environmental fungi-based biorefinery
- 2022
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Ingår i: Journal of Environmental Management. - : Elsevier BV. - 0301-4797 .- 1095-8630. ; 303
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Tidskriftsartikel (refereegranskat)abstract
- Vinasse and whey are wastewaters that are produced in large quantities in the sugar-to-ethanol and dairy industries, respectively. They pose a considerable threat to the environment due to the high concentration of nutrients and COD. In this study, the potential of producing protein-rich fungal biomass and biomethane from vinasse and whey through a two-stage biorefinery was examined. In the first stage, an edible and safe for human filamentous fungus, Neurospora intermedia, was cultivated on these wastewaters. To maximize the fungal biomass yield, the cultivation parameters, i.e., pH, vinasse to whey ratio, incubation time, and nutrients supplementation, were optimized. The highest yield of 12.0 g biomass per L of wastewaters was obtained by cultivation at pH 6.5 and vinasse to whey ratio of 25:75 (v/v) for 96 h with nitrogen source supplementation. The N. intermedia biomass contained about 45% protein and noticeable essential amino acid contents, comparable to commercial sources of protein for aquatic feed such as soybean meal and fishmeal. In the second stage, the effluent of fungal cultivation was anaerobically digested to produce 425 mL/g VS biomethane. Overall, 1 m3 of wastewater yielded 5.4 kg crude protein and 10.3 m3 methane, accompanied by 93.3% COD removal.
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| 18. |
- Jafari, V., et al.
(författare)
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Construction and demolition lignocellulosic wastes to bioethanol
- 2011
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Ingår i: Renewable Energy. - : Elsevier BV. - 0960-1481 .- 1879-0682. ; 36:11, s. 2771-2775
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Tidskriftsartikel (refereegranskat)abstract
- This work deals with conversion of four construction and demolition (C&D) lignocellulosic wastes including OSB, chipboard, plywood, and wallpaper to ethanol by separate enzymatic hydrolysis and fermentation (SHF). Similar to other lignocelluloses, the wastes were resistant to the enzymatic hydrolysis, in which only up to 7% of their cellulose was hydrolyzed. Therefore, the lignocellulosic wastes were treated with phosphoric acid, sodium hydroxide, or N-methylmorpholine-N-oxide (NMMO), which resulted in improving the subsequent enzymatic hydrolysis to 38.2-94.6% of the theoretical yield. The best performance was obtained after pretreatment by concentrated phosphoric acid, followed by NMMO. The pretreated and hydrolyzed C&D wastes were then successfully fermented by baker's yeast to ethanol with 70.5-84.2% of the theoretical yields. The results indicate the possibility of producing 160 ml ethanol from each kg of the C&D wastes at the best conditions.
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| 19. |
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| 20. |
- Jeihanipour, Azam, et al.
(författare)
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Acid Hydrolysis of Cellulose-based Waste Textiles
- 2011
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Konferensbidrag (refereegranskat)abstract
- The present study focused on conversion of cellulosic part of waste textiles into biogas and its challenges. The annual global fiber consumption exceeded 70 Mt with a cellulosic fraction of around 40%. This huge amount of fiber is further processed into apparel, home textiles and industrial products and after a certain time delay end up in waste streams. This amount of cellulose has the potential of production of approximately 20 billion liters of ethanol. Assuming a good collection and waste management system, however, there are still challenges facing the process of conversion. For instance, high crystallinity of cotton cellulose makes it hard to achieve enzymatic or bacterial hydrolysis. In addition, waste textiles are composed of different materials including natural and synthetic fibers, and the cellulosic fibers should be separated from the other materials. Furthermore, presence of dyes and reagents in the fibers can also be challenging in the bioprocessing of textile waste. In the present work, we examined the process of dilute acid hydrolysis of viscose and cotton (i.e. jeans) textiles. Hydrolyses were performed at different lengths of time (8 and 15 min), temperatures (180 and 200 °C), and acid concentrations (0.5, 1.5, and 3% w/w). Hydrolysis of viscose and jeans under identical conditions resulted in significantly different yields of glucose. This may be due to differences in the structure, i.e. high crystalline cellulose in jeans and low crystalline cellulose in viscose.
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| 21. |
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| 22. |
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| 23. |
- Jeihanipour, Azam, et al.
(författare)
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Efficient ethanol production from spruce by N-methylmorpholine-N-oxide (NMMO) pretreatment
- 2011
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Pretreatment of lignocelluloses with cellulose dissolution reagents is efficient and can be applied under relatively mild conditions. NMMO is an industrial cellulose solvent that can dissolve cellulose by breaking intramolecular bonds. The solvent can be recycled with over 99% recovery and does not produce toxic waste pollutants. After dissolution, the cellulose can be regenerated by fast precipitation with an anti-solvent that is usually water. The dissolution can severely modify the structure of cellulose and reduce its crystallinity, which is very important in hydrolysis of softwoods. Native species of spruce was debarked, cut, milled, and screened to achieve a size of less than 1 mm. The treatment was performed using 85%w/w NMMO solution at 120ºC for 1, 3, and 15 h. The pretreated wood species were then regenerated by addition of boiling distilled water, followed by vacuum filtration and washing. The pretreated and untreated wood species were enzymatically hydrolyzed by commercial cellulase (15 FPU/g) and β-glucosidase (30 IU/g) at 45°C for 96 h. Then, the hydrolyzates were fermented by a flocculation strain of Saccharomyces cerevisiae (CCUG 53310) at 30°C for 24 h. The results showed that the pretreatment, in general, did not significantly affect the composition of the wood, while increased the yield of hydrolysis and fermentation. The cellulose hydrolysis was increased from 11% for native spruce to more than 98% for the wood treated with NMMO for 15 h, and, correspondingly, the yield of ethanol production was increased from 8.1% to over 86.1%.
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| 24. |
- Jeihanipour, Azam, 1982, et al.
(författare)
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Enhancement of ethanol and biogas production from high-crystalline cellulose by different modes of NMMO pretreatment
- 2010
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Ingår i: Biotechnology and Bioengineering. - : Wiley. - 0006-3592 .- 1097-0290. ; 105:3, s. 469-476
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Tidskriftsartikel (refereegranskat)abstract
- Pretreatment of high-crystalline cellulose with N-methyl-morpholine-N-oxide (NMO or NMMO) to improve bioethanol and biogas production was investigated. The pretreatments were performed at 90 and 120°C for 0.5–15 h in three different modes, including dissolution (85% NMO), ballooning (79% NMO), and swelling (73% NMO). The pretreated materials were then enzymatically hydrolyzed and fermented to ethanol or anaerobically digested to biogas (methane). The pretreatment at 85% NMO, 120°C and 2.5 h resulted in 100% yield in the subsequent enzymatic hydrolysis and around 150% improvement in the yield of ethanol compared to the untreated and water-treated material. However, the best results of biogas production were obtained when the cellulose was treated with swelling and ballooning mode, which gave almost complete digestion in 15 days. Thus, the pretreatment resulted in 460 g ethanol or 415 L methane from each kg of cellulose. Analysis of the structure of treated and untreated celluloses showed that the dissolution mode can efficiently convert the crystalline cellulose I to cellulose II. However, it decreases the water swelling capacity of the cellulose. On the other hand, swelling and ballooning modes in NMO treatment were less efficient in both water swelling capacity and cellulose crystallinity. No cellulose loss, ambient pressure, relatively moderate conditions, and high efficiency make the NMO a good alternative for pretreatment of high-crystalline cellulosic materials.
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| 25. |
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| 26. |
- Karimi, Keikhosro, et al.
(författare)
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A critical review of analytical methods in pretreatment of lignocelluloses : Composition, imaging, and crystallinity.
- 2016
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Ingår i: Bioresource Technology. - : Elsevier BV. - 0960-8524 .- 1873-2976. ; 200
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Tidskriftsartikel (refereegranskat)abstract
- Lignocelluloses are widely investigated as renewable substrates to produce biofuels, e.g., ethanol, methane, hydrogen, and butanol, as well as chemicals such as citric acid, lactic acid, and xanthan gum. However, lignocelluloses have a recalcitrance structure to resist microbial and enzymatic attacks; therefore, many physical, thermal, chemical, and biological pretreatment methods have been developed to open up their structure. The efficiency of these pretreatments was studied using a variety of analytical methods that address their image, composition, crystallinity, degree of polymerization, enzyme adsorption/desorption, and accessibility. This paper presents a critical review of the first three categories of these methods as well as their constraints in various applications. The advantages, drawbacks, approaches, practical details, and some points that should be considered in the experimental methods to reach reliable and promising conclusions are also discussed.
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| 27. |
- Karimi, Keikhosro, et al.
(författare)
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A critical review on analysis in pretreatment of lignocelluloses : Degree of polymerization, adsorption/desorption, and accessibility
- 2016
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Ingår i: Bioresource Technology. - : Elsevier BV. - 0960-8524 .- 1873-2976. ; 203, s. 348-356
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Tidskriftsartikel (refereegranskat)abstract
- The pretreatment of lignocelluloses results in changes in the different properties of these materials. In a recent review (Karimi and Taherzadeh, 2016), the details of compositional, imaging, and crystallinity analyses of lignocelluloses were reviewed and critically discussed. Changes in the cellulose degree of polymerization, accessibility, and enzyme adsorption/desorption by pretreatments are also among the effective parameters. This paper deals with the measurement techniques, modifications, and relation to bioconversions, as well as the challenges of these three properties. These analyses are very helpful to investigate the pretreatment processes; however, the pretreatments are very complicated and challenging processes. It is not easily possible to study the effects of only one of these parameters and even to find which one is the dominant one. Moreover, it is not possible to accurately predict the changes in the bioconversion yield using these methods.[on SciFinder (R)]
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| 28. |
- Karimi, Keikhosro, et al.
(författare)
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Fed-batch cultivation of Mucor indicus in dilute-acid lignocellulosic hydrolyzate for ethanol production
- 2005
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Ingår i: BIOTECHNOLOGY LETTERS. - : Springer Science and Business Media LLC. - 0141-5492 .- 1573-6776. ; 27:18
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Tidskriftsartikel (refereegranskat)abstract
- Mucor indicus fermented dilute-acid lignocellulosic hydrolyzates to ethanol in fed-batch cultivation with complete hexose utilization and partial uptake of xylose. The fungus was tolerant to the inhibitors present in the hydrolyzates. It grew in media containing furfural (1 g/l), hydroxymethylfurfural (1 g/l), vanillin (1 g/l), or acetic acid (7 g/l), but did not germinate directly in the hydrolyzate. However, with fed-batch methodology, after initial growth of M. indicus in 500 ml enzymatic wheat hydrolyzate, lignocellulosic hydrolyzate was fermented with feeding rates 55 and 100 ml/h. The fungus consumed more than 46% of the initial xylose, while less than half of this xylose was excreted in the form of xylitol. The ethanol yield was 0.43 g/g total consumed sugar, and reached the maximum concentration of 19.6 g ethanol/l at the end of feeding phase. Filamentous growth, which is regarded as the main obstacle to large-scale cultivation of M. indicus, was avoided in the fed-batch experiments.
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| 29. |
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| 30. |
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| 31. |
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| 32. |
- Karimi, Keikhosro, et al.
(författare)
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Recent trends in acetone, butanol, and ethanol (ABE) production
- 2015
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Ingår i: Biofuel Research Journal. ; 2:4, s. 301-308
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Tidskriftsartikel (refereegranskat)abstract
- Among the renewable fuels considered as a suitable substitute to petroleum-based gasoline, butanol has attracted a great deal of attention due to its unique properties. Acetone, butanol, and ethanol (ABE) can be produced biologically from different substrates, including sugars, starch, lignocelluloses, and algae. This process was among the very first biofuel production processes which was commercialized during the First World War. The present review paper discusses the different aspects of the ABE process and the recent progresses made. Moreover, the microorganisms and the biochemistry of the ABE fermentation as well as the feedstocks used are reviewed. Finally, the challenges faced such as low products concentration and products` inhibitory effects on the fermentation are explained and different possible solutions are presented and reviewed.
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| 33. |
- Khodaverdi, M., et al.
(författare)
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Kinetic modeling of rapid enzymatic hydrolysis of crystalline cellulose after pretreatment by NMMO
- 2012
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Ingår i: Journal of Industrial Microbiology and Biotechnology. - : Oxford University Press (OUP). - 1367-5435 .- 1476-5535 .- 0973-7510. ; 39:3, s. 429-438
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Tidskriftsartikel (refereegranskat)abstract
- Pretreatment of cellulose with an industrial cellulosic solvent, N-methylmorpholine-N-oxide, showed promising results in increasing the rate of subsequent enzymatic hydrolysis. Cotton linter was used as high crystalline cellulose. After the pretreatment, the cellulose was almost completely hydrolyzed in less than 12 h, using low enzyme loading (15 FPU/g cellulose). The pretreatment significantly decreased the total crystallinity of cellulose from 7.1 to 3.3, and drastically increased the enzyme adsorption capacity of cellulose by approximately 42 times. A semi-mechanistic model was used to describe the relationship between the cellulose concentration and the enzyme loading. In this model, two reactions for heterogeneous reaction of cellulose to glucose and cellobiose, and a homogenous reaction for cellobiose conversion to glucose was incorporated. The Langmuir model was applied to model the adsorption of cellulase onto the treated cellulose. The competitive inhibition was also considered for the effects of sugar inhibition on the rate of enzymatic hydrolysis. The kinetic parameters of the model were estimated by experimental results and evaluated.
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| 34. |
- Kumar, Rajeev, et al.
(författare)
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Recent updates on lignocellulosic biomass derived ethanol-A review
- 2016
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Ingår i: Biofuel Research Journal. - 2292-8782. ; 3:1, s. 347-356
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Tidskriftsartikel (refereegranskat)abstract
- Lignocellulosic (or cellulosic) biomass derived ethanol is the most promising near/long term fuel candidate. In addition, cellulosic biomass derived ethanol may serve a precursor to other fuels and chemicals that are currently derived from unsustainable sources and/or are proposed to be derived from cellulosic biomass. However, the processing cost for second generation ethanol is still high to make the process commercially profitable and replicable. In this review, recent trends in cellulosic biomass ethanol derived via biochemical route are reviewed with main focus on current research efforts that are being undertaken to realize high product yields/titers and bring the overall cost down.
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| 35. |
- Lennartsson, Patrik R, 1983, et al.
(författare)
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Effects of different growth forms of Mucor indicus on cultivation on dilute-acid lignocellulosic hydrolyzate, inhibitor tolerance, and cell wall composition
- 2009
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Ingår i: Journal of Biotechnology. - : Elsevier BV. - 0168-1656 .- 1873-4863. ; 143:4, s. 255-261
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Tidskriftsartikel (refereegranskat)abstract
- The dimorphic fungus Mucor indicus was grown in different forms classified as purely filamentous, mostly filamentous, mostly yeast-like and purely yeast-like, and the relationship between morphology and metabolite production, inhibitor tolerance and the cell wall composition was investigated. Low concentrations of spores in the inoculum with subsequent aeration promoted filamentous growth, whereas higher spore concentrations and anaerobic conditions promoted yeast-like growth. Ethanol was the main metabolite with glycerol next under all conditions tested. The yields of ethanol from glucose were between 0.39 and 0.42 g g(-1) with productivities of 3.2-5.0 g l(-1) h(-1). The ethanol productivity of mostly filamentous cells was increased from 3.9 to 5.0 g l(-1) h(-1) by the presence of oxygen, whereas aeration of purely yeast-like cells showed no such effect. All growth forms were able to tolerate 4.6 g l(-1) furfural and 10 g l(-1) acetic acid and assimilate the sugars, although with different consumption rates. The cell wall content of the fungus measured as alkali insoluble materials (AIM) of the purely yeast-like cells was 26% of the biomass, compared to 8% of the pure filaments. However, the chitosan concentration of the filaments was 29% of the AIM, compared to 6% of the yeast-like cells.
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| 36. |
- Lennartsson, Patrik R, 1983, et al.
(författare)
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Ethanol production from lignocellulose by the dimorphic fungus Mucor indicus
- 2008
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Ingår i: World Bioenergy. Jönköping, Sweden, 27-29 May, 2008.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Ethanol production from dilute-acid hydrolyzate by the dimorphic fungus Mucor indicus was investigated. A mixture of different forest wood chips dominated by spruce was hydrolyzed with 0.5 g/L sulfuric acid at 15 bar for 10 min, yielding different sugars including galactose, glucose, mannose, and xylose, but also different fermentation inhibitors such as acetic acid, furfural, hydroxymethyl furfural (HMF), and phenolic compounds. We induced different morphological growth of M. indicus from purely filamentous, mostly filamentous, mostly yeast-like to purely yeast-like. The different forms were then ysed to ferment the hydrolyzate. They tolerated the presence of the inhibitors under anaerobic batch cultivation well and the ethanol yield was 430-440 g/kg consumed sugars. The ethanol productivity depended on the morphology. Judging from these results, we conclude that M. indicus is useful for ethanol production from toxic substrates independent of its morphology.
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| 37. |
- Mirahmadi, K., et al.
(författare)
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Alkaline Pretreatment of Spruce and Birch to Improve Bioethanol and Biogas Production
- 2010
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Ingår i: BioResources. - : Wiley. - 1930-2126 .- 1930-2126. ; 5:2, s. 928-938
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Tidskriftsartikel (refereegranskat)abstract
- Alkaline pretreatment with NaOH under mild operating conditions was used to improve ethanol and biogas production from softwood spruce and hardwood birch. The pretreatments were carried out at different temperatures between minus 15 and 100 degrees C with 7.0% w/w NaOH solution for 2 h. The pretreated materials were then enzymatically hydrolyzed and subsequently fermented to ethanol or anaerobically digested to biogas. In general, the pretreatment was more successful for both ethanol and biogas production from the hardwood birch than the softwood spruce. The pretreatment resulted in significant reduction of hemicellulose and the crystallinity of cellulose, which might be responsible for improved enzymatic hydrolyses of birch from 6.9% to 82.3% and spruce from 14.1% to 35.7%. These results were obtained with pretreatment at 100 degrees C for birch and 5 degrees C for spruce. Subsequently, the best ethanol yield obtained was 0.08 g/g of the spruce while pretreated at 100 degrees C, and 0.17 g/g of the birch treated at 100 degrees C. On the other hand, digestion of untreated birch and spruce resulted in methane yields of 250 and 30 l/kg VS of the wood species, respectively. The pretreatment of the wood species at the best conditions for enzymatic hydrolysis resulted in 83% and 74% improvement in methane production from birch and spruce.
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| 38. |
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| 39. |
- Mirmohamadsadeghi, Safoora, et al.
(författare)
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Enhanced solid-state biogas production from lignocellulosic biomass by organosolv pretreatment
- 2014
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Ingår i: BioMed Research International. - : Hindawi Limited. - 2314-6133 .- 2314-6141. ; 2014
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Tidskriftsartikel (refereegranskat)abstract
- Organosolv pretreatment was used to improve solid-state anaerobic digestion (SSAD) for methane production from three different lignocellulosic substrates (hardwood elm, softwood pine, and agricultural waste rice straw). Pretreatments were conducted at 150 and 180°C for 30 and 60 min using 75% ethanol solution as an organic solvent with addition of sulfuric acid as a catalyst. The statistical analyses showed that pretreatment temperature was the significant factor affecting methane production. Optimum temperature was 180°C for elmwood while it was 150°C for both pinewood and rice straw. Maximum methane production was 152.7, 93.7, and 71.4 liter per kg carbohydrates (CH), which showed up to 32, 73, and 84% enhancement for rice straw, elmwood, and pinewood, respectively, compared to those from the untreated substrates. An inverse relationship between the total methane yield and the lignin content of the substrates was observed. Kinetic analysis of the methane production showed that the process followed a first-order model for all untreated and pretreated lignocelluloses.
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| 40. |
- Mirmohamadsadeghi, Safoora, et al.
(författare)
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Improvement of Solid-State Biogas Production from Wood by Concentrated Phosphoric Acid Pretreatment
- 2016
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Ingår i: BioResources. - : BioResources. - 1930-2126. ; 11:2, s. 3230-3243
-
Tidskriftsartikel (refereegranskat)abstract
- Cellulose Solvent-And organic Solvent-Based lignocellulose fractionation (COSLIF) has been repeatedly shown to be a Cost-Effective and promising process to modify the structure of different lignocelluloses. It has been repeatedly reported to improve enzymatic hydrolysis and ethanol production from different lignocelluloses. In this study, COSLIF was used to improve biomethane production from pine (softwood), poplar (soft hardwood), and berry (hard hardwood) via solid state anaerobic digestion (SSAD). Feed to inoculum (F/I) ratio, which plays a major role in SSAD, was set to 3, 4, and 5. After the pretreatment, 39, 33, and 24% higher methane yield from pine was achieved for F/I ratios of 3, 4, and 5, respectively. However, the methane yield from the hardwoods was not improved by the pretreatment, which was related to overloading of the digester. Compositional analysis showed considerable reduction in hemicellulose and lignin content by the pretreatment. Structural changes in the woods, before and after the pretreatment, were examined by X-Ray diffractometer and scanning electron microscopy. The results showed that the crystallinity of cellulose was decreased and accessible surface area was drastically increased by the pretreatment.
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| 41. |
- Mohamadi, Marzieh, 1988, et al.
(författare)
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A morpholinium ionic liquid for rice straw pretreatment to enhance ethanol production
- 2019
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Ingår i: Industrial Crops and Products. - : Elsevier BV. - 0926-6690 .- 1872-633X. ; 139
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Tidskriftsartikel (refereegranskat)abstract
- Rice straw was successfully pretreated with a novel and inexpensive morpholinium ionic liquid, 1-H-3-methylmorpholinium chloride ([HMMorph][Cl]). The influence of water (30, 40, 50% w/w) and dimethyl sulfoxide (DMSO) (10, 30% w/w), as co-solvents, pretreatment time (2, 3, 5 h), temperature (90, 105, 120 °C), solid loading (5, 6.7, 10% w/w), and straw particle size (<0.177, 0.177–0.841 mm, and 0.841–2 mm) were investigated for maximum ethanol production. The best results were obtained in 50% water, at 120 °C and 5% (w/w) solid loading for 5 h from 0.177 – 0.841 mm straw particles. The hydrolysis yield was increased from 33.2% to 70.1%, while ethanol production yield was improved from 21.9% to 64% of the theoretical maximum. The performance of the IL was comparable to 1-ethyl-3-methylimidazolium acetate. Simple synthesis process and dilute solution required for the pretreatment with [HMMorph][Cl] offers cost reductions in the use of ILs in biofuel production.
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| 42. |
- Mohamadi, Marzieh, 1988, et al.
(författare)
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Improvement of ethanol production from birch and spruce pretreated with 1-H-3-methylmorpholinium chloride
- 2019
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Ingår i: Electronic Journal of Biotechnology. - : Elsevier BV. - 0717-3458. ; 41, s. 95-99
-
Tidskriftsartikel (refereegranskat)abstract
- Background : Pretreatment is the critically important step for the production of ethanol from lignocelluloses. In this study, hardwood birch (Betula pendula) and softwood spruce (Norway spruce) woods were pretreated with a newly synthesized morpholinium ionic liquid, 1-H-3-methylmorpholinium chloride ([HMMorph][Cl]), followed by enzymatic hydrolysis and fermentation to ethanol. Results : [HMMorph][Cl] was synthesized using inexpensive raw materials, i.e., hydrochloric acid and N-methyl morpholine, following a simple process. The influence of pretreatment time (2, 3, 5, and 8 h) and temperature (120 and 140°C) in terms of hydrolysis efficiency was investigated. Glucose yields from enzymatic hydrolysis were improved from 13.7% to 45.7% and 12.9% to 51.8% after pretreatment of birch and spruce woods, respectively, under optimum pretreatment conditions (i.e., at 140°C for 3 h) as compared to those from pristine woods. Moreover, the yields of ethanol production from birch and spruce were increased to 34.8% and 44.2%, respectively, while the yields were negligible for untreated woods. Conclusions : This study demonstrated the ability of [HMMorph][Cl] as an inexpensive agent to pretreat both softwood and hardwood.
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| 43. |
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| 44. |
- Molaverdi, Maryam, et al.
(författare)
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High efficient ethanol production from corn stover by modified mild alkaline pretreatment
- 2021
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Ingår i: Renewable Energy. - : Elsevier BV. - 0960-1481. ; 170, s. 714-723
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Tidskriftsartikel (refereegranskat)abstract
- Sodium carbonate pretreatment, an environmentally-friendly and efficient pretreatment, was used to improve solid-state ethanol production from corn stover (CS). To further enhance ethanol yield from the pretreated CS, especially at low enzyme loadings, a combined pretreatment, including steam and sodium carbonate pretreatments, was developed. The removal/modification of lignin by sodium carbonate pretreatment (at 100 °C for 3 h) helped to obtain high ethanol titer at high solids and low enzymes loadings. The maximum ethanol concentration was about 44 g/L, obtained after 72 h simultaneous saccharification and fermentation (SSF) of CS pretreated with sodium carbonate without mixing and prehydrolysis at 30% solid and 15 FPU/g enzyme loadings. Applying prehydrolysis and increasing the SSF time to 120 h improved ethanol concentration to 59 and 67 g/L, respectively. Steam pretreatment at 190 °C for 10 min before sodium carbonate pretreatment led to 76% increase in ethanol concentration. At the enzyme loading of only 5 FPU/g substrate, the modified pretreatment increased the ethanol concentration from 24 g/L to 41 g/L, compared with that of sodium carbonate pretreatment. The results showed that hemicellulose removal and delignification by steam and sodium carbonate pretreatment, respectively, considerably improved ethanol concentration at high solids and low enzyme loadings.
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| 45. |
- Molaverdi, Maryam, et al.
(författare)
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High titer ethanol production from rice straw via solid-state simultaneous saccharification and fermentation by Mucor indicus at low enzyme loading
- 2019
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Ingår i: Energy Conversion and Management. - : Elsevier BV. - 0196-8904. ; 182, s. 520-529
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Tidskriftsartikel (refereegranskat)abstract
- High titer ethanol production from rice straw using Mucor indicus fungus was investigated through the solid-state simultaneous saccharification and fermentation (SSSF) process. The straw was pretreated with 0.5 M sodium carbonate solution for 3, 5, and 10 h to improve the efficiency of the process. Effects of the pretreatment on the composition, structural morphology, cellulose crystallinity, swelling capacity, and buffering capacity of the straw were studied. Moreover, the effects of SSSF reaction time, enzyme loading, and solid loading on glucose and ethanol production were investigated. Additionally, the nutritional value of the residue from the SSSF process, as an animal feedstock, was determined in terms of lipid and protein contents. The highest total sugar concentration was 89.2 g/L, obtained from the straw pretreated for 10 h after hydrolysis with 10 FPU/g straw at 15% (w/w) solid loading. Total sugars concentration was not significantly improved by increasing the pretreatment time at low enzyme loadings, whereas it was significantly improved at high enzyme loadings. The highest ethanol concentration and SSSF yield were 99.4 g/L and 89.5% (71.8% based on the raw material), achieved from the straw pretreated for 10 h through the 72-h SSSF at 30% and 15% solid loading, respectively, using 20 FPU/g straw. The low enzyme loadings of 2.5 and 5 FPU/g straw yielded ethanol with concentrations as high as 66.3 and 90.9 g/L, respectively, after 120-h fermentation at 30% solid loading from the straw pretreated for 5 h.
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| 46. |
- Paraj, Aliakbar, et al.
(författare)
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Reverse micellar extraction of fungal glucoamylase produced in solid state fermentation culture
- 2014
-
Ingår i: Journal of Microbiology and Biotechnology. - : Han'gug Mi'saengmul Saengmyeong Gong Haghoe,Korean Society for Microbiology and Biotechnology. - 1017-7825 .- 1738-8872. ; , s. in press-
-
Tidskriftsartikel (refereegranskat)abstract
- Partial purification of glucoamylase from solid-state fermentation culture was, firstly, investigated by reverse micellar extraction (RME). To avoid back extraction problems, the glucoamylase was kept in original aqueous phase, while the other undesired proteins/enzymes were moved to reverse micellar organic phase. The individual and interaction effects of main factors, i.e. pH and NaCl concentration in aqueous phase, and concentration of AOT (sodium bis-2-ethyl-hexyl-sulphosuccinate) in organic phase were studied using response surface methodology. The optimum conditions for the maximum recovery of the enzyme were pH 2.75, 100 mM NaCl, and 200 mM AOT. Furthermore, the optimum organic to aqueous volume ratio (Vorg/Vaq) and appropriate number of sequential extraction stages were 2 and 3, respectively.Finally, 60% of the undesired enzymes including proteases and xylanases were removed from aqueous phase, while 140% of glucoamylase activity was recovered in aqueous phase and the purification factor of glucoamylase was found to be 3.0-fold.
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| 47. |
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| 48. |
- Poornejad, Nafiseh, et al.
(författare)
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Improvement of Ethanol Production from Spruce by Solvent Pretreatment
- 2010
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Lignocelluloses are abundant and inexpensive resources that can be used for production of bioethanol. However, these materials, especially softwoods, are resistant to enzymatic hydrolysis and a pretreatment process is necessary for efficient conversion to ethanol. The pretreatment is intended to render the cellulose amenable to enzymatic hydrolysis and subsequent fermentation to bioethanol. Several methods has been suggested for the pretreatment of lignocelluloses. The pretreatment with cellulose solvents are among the promising methods since they can perform in mild processing conditions. N-Methylmorpholine-N-oxide (NMMO) is among the industrial solvents which can dissolve cellulose by breaking intermolecular interactions. NMMO is nowadays used in the industrial Lyocell process, which is one of the modern and environmentally friendly industrial fiber-making technologies. It does not produce any toxic waste pollutants, and can be recovered over 98%. The pretreatment of lignocellulose by NMMO can modify the crystal structure of cellulose. In the current work a commercial grade 50% (W/W) NMMO solution was used for pretreatment of spruce. The NMMO solution was concentrated by vacuum evaporation to 85% NMMO. The pretreatment performed at 120ºC for 3 h. The pretreated wood species were then regenerated by addition of boiling distilled water, followed by vacuum filtration and washing. The pretreated and untreated spruce species were enzymatically hydrolyzed by commercial cellulase (celluclast 1.5L, Novozyme, Denmark) and Β-glucosidase (Novozyme 188, Novozyme, Denmark) at 45ºC for 96h. A thermotolerant strain of Saccharomyces cerevisiae was used for fermentation. Inoculum was aerobically cultivated at 30 °C and 120 rpm for 24 h. The enzymatic hydrolyzate was supplemented with necessary nutrient and fermented by the yeast for 24h at 30 °C and 120 rpm. The liquid samples were analyzed by HPLC. The results showed that the yield of ethanol increased from 7.2 g/g to 77 g/g, when the wood treated with the solvent. Formation of glycerol and other metabolites were also detected and discussed. It can be concluded that the method can be a promising alternative for pretreatment of softwoods for bioethanol production.
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| 49. |
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| 50. |
- Rodríquez, Emir Cabrera, et al.
(författare)
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Improvement of Enzymatic Hydrolysis of Spruce by Sodium Hydroxide Pretreatment at Low Temperature
- 2010
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The supply of fermentable sugars is likely to be a limiting factor for large-scale production of biofuels such as bioethanol. Therefore, processes are being developed to produce sugars from lignocellulose material by enzymatic hydrolysis. However, the cellulose fraction of lignocelluloses are not readily accessible for the hydrolyzing enzymes. Efficient hydrolysis of lignocelluloses requires pretreatment, since these materials are resistant to enzymatic hydrolysis. Several processes have been investigated for this pretreatment, in which alkali processes are among the promissing methods. In the current work, effect of NaOH pretreatment of spruce on the chemical composition and the subsequent enzymatic hydrolysis was investigated. Native spruce specie (Picea abies) was obtained from the forest around the city of Borås in Sweden. They were debarked and ball milled. The wood species was analyzed for carbohydrate and lignin fractions according to NREL methods. The wood species was chemically pretreated using 7% sodium hydroxide solution with 5% solid content at 0°C for 30, 60, 120 and 180 minutes. After the pretreatment, the residual solids were washed with distilled water to remove chemicals and neutralized to pH 7. The neutralized samples were filtered and stored for subsequent hydrolysis. Enzymatic hydrolysis of the pretreated wood was carried out at pH 4.8, 45°C and 5% dry substances. Commercial enzymes, cellulase (Celluclast 1.5L, Novozyme, Denmark) and β- glucosidase (Novozyme 188, Novozyme, Denmark) were used in the enzymatic hydrolysis. 30 FPU cellulase and 50 IU b-glucosidase per grams of the wood species were used for enzymatic hydrolysis. The pretreatments resulted in changes on the composition of the material. There were less than 1% losses in carbohydrate, suggesting no significant carbohydrate hydrolysis. Xylans were the most affected components by the pretreatments. The largest xylan removal was almost 50%, and it was occurred by using sodium hydroxide solution for 180 minutes. The profile of released sugars were also analyzed and compared. Significant improvement on the yield of enzymatic hydrolysis was observed as a results of the pretreatment.
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