초록
<P><B>Abstract</B></P> <P>β-Xylosidase activity is deficient in most cellulase enzymes secreted by filamentous fungi, which limits effective enzymatic hydrolysis of hemicellulose in lignocellulose materials and resulted in accumulation of xylo-oligosaccharides that inhibit the cellulase and xylanase activitives. An endogenous β-xylosidase gene, <I>xyl3A</I>, was overexpressed using two types of promoters in cellulolytic <I>P. oxalicum</I> RE-10. The mutants RXyl, RGXyl-1 and RGXyl-2 displayed higher β-xylosidase production than native strain RE-10 besides higher cellulase and xylanase activities, especially RGXyl-1, showing the highest β-xylosidase activity of 15.05±1.79IU/mL, about 29 folds higher than native strain, more than the highest level reported by literature. Enzymatic hydrolysis results indicated the cellulase RGXyl-1 not only increased glucose and xylose yields and thus resulted in high ethanol yield during the simultaneous saccharification and fermentation, but decreased the total enzyme loading compared to starting RE-10, which indicated a good prospect of industrial application in bioconversion of lignocellulose.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A β-xylosidase hyper-production <I>P. oxalicum</I> RGXyl-1 mutant was constructed. </LI> <LI> Activity of β-xylosidase in the study was more than the highest level in literatures. </LI> <LI> Overall production of cellulase and xylanase were also increased by the mutant. </LI> <LI> Cellulase RGXyl-1 can effectively degrade corn stover and improve ethanol production. </LI> </UL> </P>