Optimization of fermentation conditions for production of xylanase by a newly isolated strain, Penicillium thiersii ZH-19

The objective of this study was to maximize production of xylanase by a newly isolated strain Penicillium thiersii ZH-19. Response surface methodology was employed to study the effects of significant factors such as pH, temperature, xylan concentration, and cultivation time, on the production of xylanase by Penicillium thiersii ZH-19. The optimal fermentation parameters for enhanced xylanase production were found to be pH 7.72, temperature 24.8°C, xylan 13.2 g l−1 and the fermentation time 125.8 h. The model predicted a xylanase activity of 75.24 U ml−1. Verification of the optimization showed that the maximum xylanase production reached 73.50 U mL−1 in the flask experiments and 80.23 U mL−1 in the scale of 15-L fermenter under the optimal condition.