Isolation of xylanase-producing thermo-tolerant Bacillus sp. and its enzyme production

摘要

Thermo-tolerant bacterium producing the xylanase was isolated from soil and identified as Bacillus pumilus. This strain, named Bacillus pumilus TX703, was able to grow and produce xylanase at the culture temperature of 50 deg C. The maximum xylanase production was obtained when 1% (w/v) birchwood xylan and 1% (w/v) soytone were used as carbon source and nitrogen source, respectively. The biosynthesis of xylanase was under the catabolite repression induced by glucose in the culture medium, and it was completely inhibited in the presence of 0.2% (w/v) glucose. The maximum activity of xylanase was observed from aH 8.0 to 9.0 and from 50 to 60 deg C and the enzyme was highly heat-stable, whose activity remained was over 50% at 80 deg C, and was quite stable from aH 5.0 to 10.0.