Effects of Temperature and Relative Humidity on the Growth of and Enzyme Production by Actinomucor taiwanensis during Sufu Pehtze Preparation.

The growth of and production of protease, alpha-amylase, alpha-galactosidase, and lipase by Actinomucor taiwanensis in relation to temperature and relative humidity during the preparation of sufu (Chinese cheese) pehtze were investigated. The incubation temperature, humidity, and cultivation time greatly affected the growth of and enzyme production by A. taiwanensis on tofu. It grew best at 97% humidity and 30 degrees C. The highest yields of protease (112 U/g of dry tofu) and lipase (1,448 U/g of dry tofu) were found after 60 h of incubation at 97% humidity and 25 degrees C. On the other hand, the highest yield of alpha-amylase (1,949 U/g of dry tofu) was observed after 48 h of incubation at 96 to 97% humidity and 30 degrees C, and the highest amount of alpha-galactosidase (387 U/g of dry tofu) was observed at 35 degrees C and 96% humidity after 60 h of growth. The results suggest that the temperature and humidity should be controlled at 25 to 30 degrees C and around 97%, respectively, during the commercial preparation of sufu pehtze for better growth of and production of enzymes by A. taiwanensis.