米根霉产脂肪酶的条件及酶学性质

对用于全细胞生物催化剂的米根霉菌株产酶条件的优化及脂肪酶的酶学性质进行了研究。结果表明，在250 mL三角瓶液体培养中，米根霉适宜的产酶条件为：氮源为2%胰蛋白胨与0.1%NaNO3复合，碳源为0.3%的大豆油，培养基初始pH=5.5，培养温度28℃，培养时间约58 h。酶学性质研究表明，所产脂肪酶的最适pH=7.5，最适温度为35℃，该酶在pH为7~9、温度低于40℃的范围内表现稳定，Mg2+对酶活力有一定促进作用。

Production conditions and enzymatic properties of lipase from Rhizopus oryzae

The whole-cell biocatalyst is a novel technology for biodiesel production. It can not only overcome the needs of high-energy and environmental pollution in traditional chemical process, but also avoid the high cost and short lifetime of enzymes in immobilized-enzyme catalyzing system. Therefore, the whole-cell biocatalyst attracts extensive attention in recent years. In this paper the production conditions of lipase from Rhizopus oryzae were optimized and its enzymatic properties were studied. The results indicated that the suitable conditions for lipase production from R. oryzae were as the follows : nitrogen source was 2% tryptone and 0.1% NaNO_3 , carbon source was 0.3% soybean, initial pH was 5.5, in-cubation temperature was 28℃, and incubation time was 58 h, respectively. Furthermore, the properties of the lipase were also characterized. The optimal pH and temperature of lipase for catalysis were 7.5 and 35℃. The lipase was rela-tively stable in pH range of 7-9 and at 40℃, and Mg~(2+) had a stimulative effect on the lipase activity.