Expression and Fermentation Condition Optimization of Xylanase xynZF-318 in Bacillus subtilis WB600

In order to obtain the recombinant Bacillus subtilis producing xylanase, a xylanase gene named xynZF-318 from Aspergillus niger was cloned into expression vector pWB980, and the recombinant vector pWB980/xynZF-318 was transformed into Bacillus subtilis WB600 by electroporation. The recombinant strain WB600/pWB980/xynZF-318 was constructed successfully. The expression conditions of the recombinant strain in shake flask was optimized by the single factor and response surface experiments. The optimal expression conditions of the engineered bacteria were as follows:Inoculum size of 1.2%, liquid volume of 20 mL, inoculum age of 11 h, culture temperature of 37℃, shaking speed of 160 r/min and fermentation time of 168 h.The enzyme activity was up to 0.359 U/mL under the optimum conditions, which improved 2.66 times compared with the wild type strain WB600. The recombinant Bacillus subtilis producing xylanase was successfully constructed, which might be expected to provide new ideas for the industrial application of xylanase, especially for the food industry.