Abstract

Enzyme precipitation is a popular method for enzyme purification in industrial scale. This method is simple and inexpensive. In this paper, protease was purified from the extract of Aspergillus oryzae surface culture. It can be concluded that ethanol was a suitable precipitating agent. With the optimal ratio of ethanol and enzyme extract - 65/35(v/v), the enzyme recovery yield was 65% and the purity degree was 3,03. The pHopt and Topt of the purified enzyme were 7,0 and 50-55°C respectively. In addition, the obtained protease was fairly salt-tolerant. In the sample with NaCl 50g/L and 100g/L, the enzyme activity remained 70% and 50% respectively in comparaison with the control sample.