Sunday, May 3, 2009
3-42
Effect of Solvent Extraction on Pretreatment Process of Pinus rigida
To confirm the effect of solvent extraction on pretreatment process, pretreatment of Pinus rigida was studied with several solvents.
Materials were ground and sieved through 40-mesh screen for the study, and Meicelase, which is commercial cellulase derived from Trichoderma viride, was used for enzymatic hydrolysis. Holocellulose/α-Cellulose content (TAPPI), lignin content, structural carbohydrates (NREL procedures), carbon types (13C NMR), crystallinity (powder XRD), extracts analysis (GC-MS) and pore-size distribution (BET) were analyzed. Materials were extracted by petroleum ether, ethyl acetate and 70% methanol solution (v/v). Pretreatment of the extracted materials were carried out in the minibomb, and 10g of materials with 200 ml of 2% dilute sulfuric acid solution (w/v) were pretreated at 200¢ªC for 90 min. Then, residual materials were used for enzymatic hydrolysis. Enzymatic hydrolysis was carried out with 1g of pretreated material in 100 mL of 50 mM acetate buffer (pH 5.0) containing 40 mg of the enzyme powder, and the samples were incubated at 45 ¢ªC of 250 rpm in a rotary shaker for 48 hr.
Enzymatic hydrolysis yield of materials pretreated by dilute acid only was 20.50, while that of the solvent extracted materials was up to 37.52%. It might indicate that solvent that used in extraction process removed some extractives which acted as an inhibitor of enzyme. Thus removal process of these extractives before pretreatment could enhance enzymatic hydrolysis yield of soft woods, especially Pinus rigida.
Materials were ground and sieved through 40-mesh screen for the study, and Meicelase, which is commercial cellulase derived from Trichoderma viride, was used for enzymatic hydrolysis. Holocellulose/α-Cellulose content (TAPPI), lignin content, structural carbohydrates (NREL procedures), carbon types (13C NMR), crystallinity (powder XRD), extracts analysis (GC-MS) and pore-size distribution (BET) were analyzed. Materials were extracted by petroleum ether, ethyl acetate and 70% methanol solution (v/v). Pretreatment of the extracted materials were carried out in the minibomb, and 10g of materials with 200 ml of 2% dilute sulfuric acid solution (w/v) were pretreated at 200¢ªC for 90 min. Then, residual materials were used for enzymatic hydrolysis. Enzymatic hydrolysis was carried out with 1g of pretreated material in 100 mL of 50 mM acetate buffer (pH 5.0) containing 40 mg of the enzyme powder, and the samples were incubated at 45 ¢ªC of 250 rpm in a rotary shaker for 48 hr.
Enzymatic hydrolysis yield of materials pretreated by dilute acid only was 20.50, while that of the solvent extracted materials was up to 37.52%. It might indicate that solvent that used in extraction process removed some extractives which acted as an inhibitor of enzyme. Thus removal process of these extractives before pretreatment could enhance enzymatic hydrolysis yield of soft woods, especially Pinus rigida.
Further analysis will be conducting to investigate the effect of solvent extraction process and to find out this obstructive extractives.
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