Abstract: Using conversion rate of ethyl hexanoate as the index, a strain Rhizopus ZM-10 producing lipase was screened out from liquor factory. We studied properties of the Rhizopus lipase after partical purification. The optimum temperature of the lipase was 25℃, and was stable below 30℃. The lipase optimal pH was 7.0 and 8.0. When metal ion concentration was 2mmol/L, its activity was increased with amendment of Na+、Cu2+、Fe3+、EDTA, and when metal ion concentration was 5mmol/L, all metal ion inhibited its activity in different degree except Cu2+. The concentration of surfactants affected lipase activity, and the type of surfactants had no significant effect of lipase activtiy. The values of Km and Vmax were 18.2mmol/L and 625U/L in optimum reaction conditions.

Key words: Rhizopus, lipase, ethyl hexanoate, purification, properties