高产脂肪酶菌株的分离筛选与培养基优化

实验进行了高产脂肪酶菌株的分离筛选与发酵条件优化的研究。通过对35份富含油脂等样品的富集培养、分离筛选，获得320株产脂肪酶的细菌、酵母菌和霉菌，其中细菌X-13产酶活力最高，约为3．5U／mL；X-13发酵产脂肪酶的最佳碳源和氮源分别为可溶性淀粉、牛肉膏，Mg^2＋、Ca^2＋、Co^2＋对X-13菌株产酶有促进作用，Fe^2＋、Mn^2＋．Cu^2＋抑制菌株产酶；正交试验设计优化的培养基成分为：可溶性淀粉6g／L、牛肉膏4g／L、酵母粉0．5g／L、MgSO4 0．2g／L、聚乙二醇（PEG400）0．6mL／L、K2HPO4 1g／L、橄榄油乳化液20mL／L、pH值为7．0。在此优化培养条件下，细菌X-13培养72h的产脂肪酶活力达到9．28U／mL，较优化前提高2．65倍。

Isolation and medium optimization of high lipase producing strain

In this study, high-yielding lipase strains were isolated and screened from food and oil contaminated soils, and fermentation conditions were optimized for maximal enzyme production. 320 lipase-producing strains of bacteria, yeasts and molds were obtained through 35 rich in oil samples, in which bacteria X-13 produced the highest enzyme activity, about 3.5U/mh The optimal carbon source for bacteria X-13 fermenting and producing lipase was soluble starch, and the optimal nitrogen source was beef extract, and Mg^2＋, Ca^2＋, Co^2＋ were found to stimulate the lipase activity, however, Fe^2＋, Mn^2＋, Cu^2＋ inhibited the lipase yield of the strain X-13. The modified complex medium by orthogonal experiment design were that soluble starch 6g/L, beef extract 4g/L, yeast extract 0.5g/L, MgSO4·7H2O 0.2g/L, polyethylene glycol （PEG400） 0.6 ml/L, K2HPO4 1g/L, olive oil emulsion 20ml/L, pH 7.0. Under the optimized culture conditions, the lipase activity of X-13 was 9.28U/ml and improved by 2.65 folds compared with the initial screened media after 72h of shaking incubation at 30℃.