Screening of xylanase producing Bacillus and study on its enzyme production conditions

A high-xylanase-producing Bacillus strain was screened by transparent zone and xylan assay on the selective medium.Its proper conditions for fermentation and reaction were investigated.Results indicated that the strains could degrade straw and wheat bran,with the degradation rates at 43.3% and 63.4% respectively.On the basis of screening for liquid culture and determination of activity,an optimal culture conditions with higher yield was obtained,which contained 2% of soybean meal,3% of tryptone,0.1% of yeast extract and 2% of glucose;The optimal temperature and pH value was 37 ℃and pH 7 respectively.With 10 L of fermentation tank,the xylanase activity was up to 3024 U/ml after 48 hours of culture,increased by 38% compared with 2185 U/ml by flask liquid fermentation.