The Optimal Liquid Fermentation Conditions for Protease Production by Asp-195v

[Objective]The aim was to optimize fermentation conditions for protease production by Asp-195v.[Method]The liquid fermentation conditions for protease production of the strain Asp-195v of Aspergillus clavatus were studied by orthogonal design method,which included medium constituent,water content,initial pH value,inoculum amount,fermentation time and temperature in 250 ml shaking bottle. [Results]The results showed that the main factor affecting protease production was fermentation time. The optimal liquid fermentation conditions in shaking bottles were as follows: the ration of bran and bean cake was 7∶3(10 grams of total),water 90 ml,initial pH 7,inoculum amount was 1.5 ml,fermentation time was 72 h,fermentation temperature was 24 ℃,rotation speed was 120 r/min. The strain Asp-195 was able to produce protease in different salinity conditions,which had a certain degree of tolerance to salt,its protease activity in 24%NaCl was 47.6% compared to the blank test without NaCl.[Conclusion] The strain had a good application value in the miso production.