Synergistic Effect between Cellulase and Xylanase Acting on Alkaline Pretreated Rice Straw

Abstract

An experiment was carried out using rice straw pretreated with 2% diluted NaOH at 28 °C for 24 h followed by a combination of commercial reagents of xylanase (Pentopan) and cellulase (Primafast 200), with the latter either purified by affinity adsorption or unpurified, for enzymatic saccharification of the pretreated rice straw. Significant synergistic effects of the enzyme combinations were observed in the released amounts of reducing sugar, glucose and xylose at a lower loading of purified Primafast 200. The synergy was shown to be the result of interaction between cellulase and xylanase. Moreover, the enzymatic performance of unpurified Primafast 200 can be also improved by the addition of Pentopan, with greater synergistic effect at 50 °C rather than at 40 °C. Sugars released by mixed enzymes treatment were more than that using unpurified Primafast 200 alone in the whole hydrolysis course, however, the hydrolysis rate superiority of mixed enzymes was mainly observed during the first 6 hours. Application of the synergistic effect between cellulase and xylanase can improve the hydrolysis efficiency and reduce the cost of enzymatic saccharification of mild alkaline pretreated rice straw.