| 1. |
- Momayez, Forough, et al.
(author)
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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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In: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 7:80, s. 50537-50545
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Journal article (peer-reviewed)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.
(author)
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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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In: Biomass and Bioenergy. - : Elsevier BV. - 0961-9534 .- 1873-2909. ; 33:5, s. 828-833
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Journal article (peer-reviewed)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.
(author)
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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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In: Revista CENIC Ciencias Químicas. - : Centro Nacional de Investigaciones Cientificas. - 2221-2442. ; 43:1, s. 1-9
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Journal article (peer-reviewed)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.
(author)
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Improvement of biogas production from oil palm empty fruit bunches (OPEFB)
- 2011
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In: Industrial crops and products (Print). - : Elsevier BV. - 0926-6690 .- 1872-633X. ; 34:1, s. 1097-1101
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Journal article (peer-reviewed)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.
(author)
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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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In: International Journal of Green Energy. - : Informa UK Limited. - 1543-5075 .- 1543-5083. ; 13:6, s. 566-572
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Journal article (peer-reviewed)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.
(author)
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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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In: Energy Conversion and Management. - : Elsevier. - 0196-8904 .- 1879-2227. ; 283
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Journal article (peer-reviewed)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.
(author)
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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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In: Bioresource Technology. - : Elsevier. - 0960-8524 .- 1873-2976. ; 368
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Journal article (peer-reviewed)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.
(author)
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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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In: 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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Journal article (peer-reviewed)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.
(author)
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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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In: Cellulose Chemistry and Technology. - 0576-9787. ; 49:9-10, s. 737-744
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Journal article (peer-reviewed)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.
(author)
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Bioethanol production from sweet sorghum bagasse by Mucor hiemalis
- 2011
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In: Industrial crops and products (Print). - : Elsevier. - 0926-6690 .- 1872-633X. ; 34:1, s. 1219-1225
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Journal article (peer-reviewed)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.
(author)
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Ethanol and biogas production from birch by NMMO pretreatment
- 2013
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In: Biomass and Bioenergy. - : Pergamon. - 0961-9534 .- 1873-2909. ; 49, s. 95-101
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Journal article (peer-reviewed)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.
(author)
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Valorization of vinasse and whey to protein and biogas through an environmental fungi-based biorefinery
- 2022
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In: Journal of Environmental Management. - : Elsevier BV. - 0301-4797 .- 1095-8630. ; 303
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Journal article (peer-reviewed)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.
(author)
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Construction and demolition lignocellulosic wastes to bioethanol
- 2011
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In: Renewable Energy. - : Elsevier BV. - 0960-1481 .- 1879-0682. ; 36:11, s. 2771-2775
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Journal article (peer-reviewed)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.
(author)
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Acid Hydrolysis of Cellulose-based Waste Textiles
- 2011
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Conference paper (peer-reviewed)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.
(author)
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Efficient ethanol production from spruce by N-methylmorpholine-N-oxide (NMMO) pretreatment
- 2011
-
Conference paper (other academic/artistic)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.
(author)
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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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In: Biotechnology and Bioengineering. - : Wiley. - 0006-3592 .- 1097-0290. ; 105:3, s. 469-476
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Journal article (peer-reviewed)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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