Co-operative actions and degradation analysis of purified lignocellulose-degrading enzymes from Thermomonospora fusca BD25 on wheat straw

Authors: MÜNİR TUNCER, ANDREW S. BALL

Abstract: In industrial hydrolysis processes the lignocellulose-degrading enzymes may have a potential application as an alternative to chemical treatments because they produce high specificity, mild reaction conditions, no toxic chemical hydrolysis inhibitors, and no loss of substrate due to chemical modifications. The amounts of reducing sugars released from the degradation of wheat straw by the action of endoxylanase, peroxidase, \beta-xylosidase, and \alpha-L-arabinofuranosidase, which were produced by T. fusca BD25,were equal to 3.0 percent, 0.2 percent, 0.3 percent, and 0.2 percent hydrolysis (as xylose equivalents) of the substrate used, respectively, after 10 h of incubation. In the same conditions, the hydrolysis rate of endoglucanase, which was a commercial preparation from Trichoderma viride was 4.9 percent. However, in order, addition of peroxidase, endoglucanase, \beta -xylosidase, and \alpha-L-arabinofuranosidase preparations to the endoxylanase preparation significantly enhanced the reducing sugar yields (1.33-, 1.52-, 1.61-, and 1.71-fold, respectively) and the hydrolysis of wheat straw (4.3 percent, 12.3 percent, 13.5 percent, and 14.7 percent, respectively). The concentrations of phenolic-compounds as lignin-equivalents released from wheat straw by the actions of lignocellulose-degrading enzyme preparations either acting alone or in combinations ranged from 2.5 to 129.3 \mug mL-1 (as p-coumaric acid equivalents). The combination of purified lignocellulose-degrading enzymes significantly increased the degradation of straw 1.33- to 1.71-fold. The results highlight the role of lignocellulose-degrading enzymes in the degradation of wheat straw and suggest that the use of enzyme cocktails may significantly improve the hydrolysis of wheat straw in industrial processes.

Keywords: Degradation, endoxylanase, lignocellulose, peroxidase, pulp, wheat straw

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