| 1. |
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| 2. |
- 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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| 3. |
- 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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| 4. |
- 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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| 5. |
- 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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| 6. |
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| 7. |
- 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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| 8. |
- 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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| 9. |
- 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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| 10. |
- 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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| 11. |
- 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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| 12. |
- 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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| 13. |
- 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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| 14. |
- Paraj, Aliakbar, et al.
(författare)
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Reverse micellar extraction of fungal glucoamylase produced in solid state fermentation culture
- 2014
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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-
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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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| 15. |
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| 16. |
- 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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| 17. |
- 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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| 18. |
- Shafiei, Marzieh, et al.
(författare)
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Enhanced Ethanol and Biogas Production from Pinewood by NMMO Pretreatment and Detailed Biomass Analysis
- 2014
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Ingår i: BioMed Research International. - : Hindawi. - 2314-6133 .- 2314-6141. ; 2014:Article ID 469378
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Tidskriftsartikel (refereegranskat)abstract
- N-Methyl morpholine-N-oxide (NMMO) is an environmentally friendly and commercially applied cellulose solvent that is suggested for pretreatment of lignocelluloses to improve biofuel productions. However, the underlying mechanisms of the improvements have been poorly understood yet. In an attempt to investigate the mechanisms, pinewood powder and chips were pretreated with 85% (w/w) NMMO at 120°C for 1–15 h. The pretreatment improved ethanol production yield from 7.2% (g/g) for the untreated wood powder to 68.1–86.1% (g/g) and from 1.7% (g/g) for the untreated wood chips to 12.6–51.2% (g/g) of theoretical yield. Similarly, the biogas yields of untreated wood chips and powder were improved from 21 and 66 (mL/g volatile solids) by 3.5–6.8- and 2.6–3.4-folds, respectively. SEM micrographs indicated major increase in the wood porosity by the pretreatment, which would confirm increase in the water swelling capacity as well as enzyme adsorption. The analysis of X-ray diffraction showed considerable reduction in the cellulose crystallinity by the pretreatment, while FTIR spectroscopy results indicated reduction of lignin on the wood surface by the pretreatment.
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| 19. |
- Shafiei, Marzieh, et al.
(författare)
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Palm Date Fibers : Analysis and Enzymatic Hydrolysis
- 2010
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Ingår i: International Journal of Molecular Sciences. - : Molecular Diversity Preservation International (MDPI) AG.. - 1661-6596 .- 1422-0067. ; 11:11, s. 4285-4296
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Tidskriftsartikel (refereegranskat)abstract
- Waste palm dates were subjected to analysis for composition and enzymatic hydrolysis of their flesh fibers. The fruit contained 32% glucose and 30% fructose, while the water-insoluble fibers of its flesh consisted of 49.9% lignin and 20.9% polysaccharides. Water-insoluble fibers were settled to 55% of its initial volume in 12 h. The presence of skin and flesh colloidal fibers results in high viscosity and clogging problems during industrial processes. The settling velocity of the fibers was improved by enzymatic hydrolysis. Hydrolysis resulted in 84.3% conversion of the cellulosic part of the fibers as well as reducing the settling time to 10 minutes and the final settled volume to 4% of the initial volume. It implies easier separation of the fibers and facilitates fermentation processes in the corresponding industries. Two kinds of high- and low-lignin fibers were identified from the water-insoluble fibers. The high-lignin fibers (75% lignin) settled easily, while the low-lignin fibers (41.4% lignin) formed a slurry suspension which settled very slowly. The hydrophilicity of these low-lignin fibers is the major challenge of the industrial processes.
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| 20. |
- Shafiei, Marzieh, et al.
(författare)
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Techno-economic study of ethanol from spruce by N-methylmorpholine-N-oxide (NMMO) pretreatment
- 2011
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Pretreatment is necessary to open up the crystalline structure of the cellulose fibers. It is believed that pretreatment is a “key process” to have an economically feasible ethanol production from lignocelluloses. N-methylmorphilne-N-oxide (NMMO) is a cellulose solvent, which has an industrial application in viscose process for fiber production. NMMO does not produce any toxic waste pollutant and is an environmentally friendly solvent. Considering NMMO as a promising alternative for pretreatment of wood, a novel process for ethanol production from wood was developed in this work. Wood is pretreated by concentrated NMMO and ethanol is produced by NSSF process. Biogas and solid residues are the valuable by products of this process. Simulation of the process with Aspen Plus® was applied to solve the process mass and energy balance; finding the bottlenecks of the process, optimizing the equipment configuration, and providing the necessary data for the equipment design. The economical feasibility of the developed biorefinery for five different plant capacities was studied by Aspen Icarus Process Evaluator®. The base case was designed to utilize 200,000 tons of spruce wood per year and needed M€ 58.3 as total capital investment. Ethanol production yield, based on experiments, was as high as one liter of ethanol per 4 kilograms of wood. Effect of price of feedstock, enzyme, methane, carbon dioxide and solid residue as well as nutrient load on the production cost were investigated.
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| 21. |
- Shafiei, Marzieh, et al.
(författare)
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Techno-economical study of biogas production improved by steam explosion pretreatment
- 2013
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Ingår i: Bioresource Technology. - : Elsevier BV. - 0960-8524 .- 1873-2976. ; 148, s. 53-60
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Tidskriftsartikel (refereegranskat)abstract
- Economic feasibility of steam explosion pretreatment for improvement of biogas production from wheat straw and paper tube residuals was investigated. The process was simulated by Aspen plus®, and the economical feasibility of five different plant capacities was studied by Aspen Process Economic Analyzer. Total project investment of a plant using paper tube residuals or wheat straw was 63.9 or 61.8 million Euros, respectively. The manufacturing cost of raw biogas for these two feedstocks was calculated to 0.36 or 0.48 €/m3 of methane, respectively. Applying steam explosion pretreatment resulted in 13% higher total capital investment while significantly improved the economy of the biogas plant and decreased the manufacturing cost of methane by 36%. The sensitivity analysis showed that 5% improvement in the methane yield and 20% decrease in the raw material price resulted in 5.5% and 8% decrease in the manufacturing cost of methane, respectively.
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| 22. |
- Shafiei, Marzieh, et al.
(författare)
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Techno-economical study of ethanol and biogas from spruce wood by NMMO-pretreatment and rapid fermentation and digestion
- 2011
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Ingår i: Bioresource Technology. - : Elsevier BV. - 0960-8524 .- 1873-2976. ; 102:17, s. 7879-7886
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Tidskriftsartikel (refereegranskat)abstract
- Given that N-methylmorpholine-N-oxide (NMMO) is a promising alternative for the pretreatment of lignocelluloses, a novel process for ethanol and biogas production from wood was developed. The solvent, NMMO, is concentrated by multistage evaporation, and the wood is pretreated with the concentrated NMMO. Thereafter, ethanol is produced by the non-isothermal simultaneous saccharification and fermentation (NSSF) method, which is a rapid and efficient process. The wastewater is treated by upflow anaerobic sludge blanket (UASB) digester for rapid production of biogas. The process was simulated by Aspen plus®. Using mechanical vapor recompression for evaporators in the pretreatment and multi-pressure distillation columns, the energy requirements for the process were minimized. The economical feasibility of the developed biorefinery for five different plant capacities was studied by Aspen Icarus Process Evaluator. The base case was designed to utilize 200,000 tons of spruce wood per year and required M€ 58.3 as the total capital investment, while the production cost of ethanol is calculated to be €/l 0.44.
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| 23. |
- Taherzadeh, Mohammad J., et al.
(författare)
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Fermentation Inhibitors in ethanol processes and different strategies to reduce their effects
- 2011
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Ingår i: Biofuels, Alternative Feedstocks and Conversion Processes. - : Elsevier Science & Technology. - 9780123850997 ; , s. 287-311
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Bokkapitel (refereegranskat)abstract
- Fermentation of lignocellulosic hydrolyzates and other carbon sources to ethanol is affected by different substances present in the cultivation media. High concentration of sugars is desirable in all ethanol processes, in order to have a higher concentration of ethanol, thus reducing the cost of distillation. However, high concentrations of both sugars and ethanol inhibit the fermentation process. Furthermore, high concentration of various salts available in most of the industrial substrates such as sugarcane juice and molasses can also make a high osmotic stress for the fermenting microorganisms. These salts and some other impurities can be further accumulated with water saving programs, in which the stillages are recycled in order to reduce water consumption and wastewater production. The choice of pretreatment and/or hydrolysis of lignocellulosic materials can lead to a number of severe inhibiting compounds, including furans, carboxylic acids, and phenolic compounds. The inhibition effects of all these components can be reduced or removed by choosing a suitable concentration of the substrates and choosing a proper method for the pretreatment and/or hydrolysis steps in order to reduce the inhibitors. If the toxic compounds follow the culture, detoxification could be an option, although it has some expenses and might lead to partial loss of the sugars. However, choosing a right strategy for the fermentation by e.g. fed-batch process or continuous mode with high-cell density or encapsulated cells as well as a tolerant organism or an organism that can convert the inhibitors might avoid the necessity of the prior detoxification.
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| 24. |
- Teghammar, Anna, 1981, et al.
(författare)
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Enhanced biogas production from rice straw, triticale straw and softwood spruce by NMMO pretreatment
- 2012
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Ingår i: Biomass and Bioenergy. - : Elsevier BV. - 1873-2909 .- 0961-9534. ; 36, s. 116-120
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Tidskriftsartikel (refereegranskat)abstract
- Softwood spruce (chips and milled), rice straw and triticale (a hybrid of rye and wheat) straw, were pretreated with N-methylmorpholine-N-oxide (NMMO or NMO) prior to anaerobic digestion to produce biogas. The pretreatments were performed at 130 degrees C for 1-15 h, and the digestions continued for six weeks. The digestions of untreated chips (10 mm) and milled (
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