초록
The enzymatic hydrolysis of lignocellulosic biomass has been studied for years, but this hydrolysis has been minimally used in the industry due to its high costs and low conversion yields. In the work reported here, ferulic acid (FA) and xylooligosaccharides (XOS) were generated from wheat bran at high yields based on the synergistic action of two xylan-degrading enzymes, xylanase (AnXyn11A) and feruloyl esterase (AnFaeA), which were cloned from Aspergillus niger BE-2 and heterologously expressed at high levels in Pichia pastoris. AnXyn11A exhibited a maximal activity of 240UmL<SUP>-1</SUP> at pH 5.0 and 60<SUP>o</SUP>C and less thermostability above 50<SUP>o</SUP>C. AnFaeA showed a maximal activity of 21UmL<SUP>-1</SUP> at pH 5.0 and 45<SUP>o</SUP>C and high thermostability below 55<SUP>o</SUP>C. The ratio of FA released from destarched wheat bran (DSWB) under the synergistic action of AnXyn11A and AnFaeA increased to 70% in comparison with that of the individual enzyme acting alone (only 16.8% of FA was released). Moreover, at the optimum level of enzyme addition, the XOS yield was double that under the single enzyme action.