Screening of a xylanase high-producing strain and its rapid separation and purification

Abstract

In this research, the xylanase high-producing strain of BE-91 (Bacillus subtilis) was selected. The enzyme activity in the fermentation liquor of BE-91 at 8 h reached 408 U/mL, which was 3.4 times higher than that of strain ACCC 10243. The xylanase was purified from BE-91 fermentation liquor with the ultrafiltration and gel chromatography, and its enzyme activity was up to 28,454 U/mg. Its recovery was above 69%, and the purification multiple of the enzyme activity was up to 18 times. The molecular weight of the purified xylanase was 22.54 kDa assayed with SDS-PAGE. The K m and V max were 0.5 mg/mL and 533 μmol/(min mL), respectively. The stabilizing pH and optimal pH of the xylanase were 4.6∼6.4 and 5.8, respectively. And when the pH was 5.8, the stabilizing temperature and optimal temperature of the xylanase were 0°C∼65°C and 60°C, respectively. Therefore it was considered that the strain BE-91 could be applied to the industrial production of xylanase. © 2011 Springer-Verlag and the University of Milan.