Control of xylanase production without protease activity in Bacillus sp. by selection of nitrogen source

Maximum xylanase activity, of 380 IU ml−1, with negligible protease activity, occurred when Bacillus SSP-34 was grown for 96 h with yeast extract and peptone each at 0.25%. Other concentrations of the combination gave xylanase activities less than 66% of that with the optimum nitrogen source concentration and protease activities in the range of 0.01–0.045 IU ml−1.