Abstract: This research was aimed to further improve the ability of protease produced by Bacillus subtilis JNB001.By series single factor and orthogonal analysis to optimize the enzyme-producing conditions from initial pH,fermentation temperature,inoculation volume,bottling volume and cell age,etc.The results showed that the optimum conditions were:Initial pH 7.0,inoculation volume of 7%,bottling volume of 35 mL in the 250 mL flask,cell age was 18 h,and cultured for 36 h at 35 ℃.Cultivated at these conditions,the protease activity of the strain JNB001 could reach to 371.66 U/mL.These consequences laid the foundation for the subsequent applications such as the design of harmless biological treatment tank,etc.

Key words: Bacillus subtilis; protease; fermentation conditions; optimization