Isolation, purification, and characterization of xylanase produced by three species of bacillus under submerged fermentation conditions

Abstract

This study focuses on the screening and identification of bacteria, which can produce alkaline xylanase at alkaline pH and high temperature. Bacterial isolates from enriched decaying soil, capable of hydrolyzing xylan were screened. Selected and purified 13 bacterial colonies (Bacilli and Kurthia) grown on xylan- nutrient agar slants, were activated and transferred into the fermentation medium. Three highest xylanase producing isolates (Bacillus badius, Kurthia gibsonii, Bacillus circulans) were selected for further studies and the xylanase produced by them were screened for their kinetic properties. The optimum temperature for the activity of the xylanase from Isolates A was 50oC; and for Isolate B was 40oC, while that of Isolate C was 30oC. The optimum pH value for the xylanase from isolate A and B was 9.0. In addition, the xylanase was also capable of producing high-quality xylo-oligosaccharides, which indicated its application potential not only in pulp bio-bleaching processes but also in the nutraceutical industry.