Isolation of alkaline xylanase producing strains and optimalization of the fermentative culture medium.

Ten strains of bacteria with xylanase activity were isolated from the soil by enrichment cultivating and the method of assaying transparent zone and the bacterial strain of Bacillus sp.No.X-18,which could produced the highest enzymatic activity,was obtained.Xylanase fermentative culture medium for the Bacillus sp.No.X-18 strain was optimized.The results showed that the optimal medium composition contained 1.5 % sucrose,1 % arabinose,0.37 % NH4Cl,0.37 % yeast extract,0.5 % K2HPO4,0.02 %MgSO4·7H2O,pH 8.0,and the enzyme activity could reach 74.21 IU/mL in the medium.