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- 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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| 2. |
- 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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