Cloning and characterization of xylanase in cellulolytic Bacillus sp strain JMY1 isolated from forest soil

Abstract

Microbes play an important role in carbon turnover in forest ecosystems by producing polysaccharide-degrading enzymes such as cellulase, xylanase, and beta-glucosidase. In the present study, we isolated a bacterial strain producing cellulase and xylanase from the Forest Park at Gyeongnam National University of Science and Technology using LB agar plates containing 0.5 % carboxymethyl cellulose and 0.01 % trypan blue. Based on 16S rRNA sequencing and API analysis, the isolated strain was identified as a Bacillus species and named Bacillus sp. JYM1. The optimal growth temperature of Bacillus sp. JYM1 was 37 degrees C. The maximal activities of carboxymethyl cellulase (CMCase) and xylanase were obtained after a 24-h cultivation. The optimal pH and temperature were 6.0 and 50 degrees C for CMCase and 5.0 and 50 degrees C for xylanase, respectively. The gene responsible for the xylanase activity in Bacillus sp. JYM1 was cloned and expressed in Escherichia coli. The expressed recombinant protein showed similar biochemical properties to the xylanase of Bacillus sp. JYM1. Therefore, our results confirmed that the gene cloned from Bacillus sp. JYM1, herein named Bxyn, encodes xylanase.