产脂肪酶菌株的筛选及其脂肪酶的双水相分离

Screening of Lipase-producing Microorganism and Lipase Extraction by Two Aqueous Two-phase Systems

从土壤中筛选到了两株产脂肪酶的菌株真菌A和真菌B。测定二者酶活,并对真菌B所产脂肪酶的双水相萃取体系进行了优化。结果表明,真菌A酶活为26.5U/mL,真菌B酶活为15.0U/mL,而真菌A比酶活为6618.62U/g,真菌B比酶活为7332.20U/g,选取真菌B为研究对象。最佳PEG分子量为2000,最佳PEG浓度为200g/L,最佳硫酸铵浓度为250g/L。

Two lipase-producing strains, named fungus A and B, were isolated from soil samples. The enzyme activities and specific activities of fungus A and B were determined. The results indicated that the lipase activity of A was higher than that of B （The lipase activity of A was 26.5U and B was 15.0U）. And the specific activity of B was higher than that of A （The specific activity of A was 6 618.62 U/g and B was 7 332.20 U/g）. As a result, fungus B was selected to optimize the aqueous two-phase system. The optimal conditions of extraction showed as follows： the molecular weight of PEG was 2 000, the concentration of PEG was 25%, and the concentration of （NH4）2SO4 was 20%.