[Study on the production of beta-mannanase by Bacillus M50]

Bacillus sp. M50 produced beta-mannanase efficiently in the medium composed of 4% konjac powder, 1.0% (NH4)2SO4 and 0.35% Na2CO3. Fermentation of beta-mannanase by Bacillus sp. M50 has been carried out in 100 L tank. The temperature, ventitation quantity and agitation speed were 30-32 degrees C, 1:0.75 vvm and 220 r/min respectively. the fermentation cycle was 28 h and the highest beta-mannanase activity was 330 u/mL. The optimal temperature and pH for beta-mannanase reaction were 50 degrees C and 6.0 respectively. It was stable at pH 4.0-7.0 and below 50 degrees C. The activity of the enzyme was strongly inhibited by Fe3+, Al3+, EDTA, Hg2+ and slightly stimulated by Ba2+, Mn2+. Treatment of ramie-fibers with crude enzyme preparations from Bacillus sp. M50 showed a good degradation for hemicellulose of ramie-fibers residues.