Fermentation conditions of neutral protease on rapeseed meal from Bacillus compatibility

In order to increase the yield of neutral protease,the fermentation conditions of strain compatibility based on rapeseed meal were optimized by single factor tests and Response Surface Methodology( RSM). The results showed that the best strain compatibility was Bacillus subtilis UV- 7 and UN- 11( 1 ∶ 1). The second- order polynomial model for neutral protease was established,and the optimal fermentation technology was obtained as following: temperature 35.7℃,rotational speed 193 r / min,and inoculum concentration 7.58%.Under the optimal conditions,the predicted yield of fitted model was 2709.9U / m L and verification test result was 2714.5 ± 2.4U / m L,which increased 4.3% compared with the original conditions.