高产脂肪酶菌株的分离筛选与培养基优化

Isolation and medium optimization of high lipase producing strain

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,Mg2+、Ca2+、Co2+对X-13菌株产酶有促进作用,Fe2+、Mn2+、Cu2+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、MgSO40.2g/L、聚乙二醇(PEG400)0.6mL/L、K2HPO41g/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。

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℃.