产脂肪酶细菌RYXP的诱变选育及突变株产酶条件优化

以"凤丹"牡丹根际土壤中分离筛选到的产脂肪酶菌株Pseudomonas sp. RYXP作为出发菌株,对其进行了紫外线诱变选育,并采用单因素试验和正交试验方法对活性最强正突变株的产脂肪酶基本特性进行了测定。结果表明,出发菌株Pseudomonas sp. RYXP的紫外线诱变最佳条件为:15 W紫外灯30 cm距离照射1 min;将产脂肪酶活性最强的正突变菌株编号为RYXP-3,单因素试验表明RYXP-3产脂肪酶适宜的碳源为玉米淀粉,适宜氮源为豆饼粉,适宜的磷酸二氢钾含量是0.3%,适宜的初始pH值为7;正交试验表明RYXP-3的最佳的产酶培养基成分组成是:玉米淀粉7%,豆饼粉3%,磷酸二氢钾0.3%,初始pH值为8。在优化方案A1B2C2D3产酶条件下,突变株RYXP-3最高的产酶活性达到56.1 U/mL。突变菌株RYXP-3可作为产油牡丹"凤丹"专用促生菌肥开发的备选资源菌株。

Mutation Breeding of Lipase Producing Bacterium RYXP and Optimization of Enzyme Production Conditions of Mutant Conditions

Pseudomonas sp.RYXP,a lipase producing strain isolated from the rhizosphere of “Fengdan”peony,was used as the starting strain which was mutagenized by ultraviolet ray,and the basic characteristics of lipase production of the positive mutant with the strongest activity were determined by single factor test and orthogonal test method.The results showed that the optimum conditions of ultraviolet radiation for Pseudomonas sp.RYXP was:at a distance of 30 cm,15 W ultraviolet lamp irradiated 1 min;the positive mutant strain with the most active lipase activity was named RYXP-3.Single factor test showed that the suitable carbon source of RYXP-3 producing lipase was corn starch,the suitable nitrogen source was bean cake powder,the appropriate content of potassium dihydrogen phosphate was 0.3%,and the proper initial pH was 7.The orthogonal test showed that the optimal enzyme medium composition of RYXP-3 was:7% of corn starch,3% of soybean meal,0.3% of potassium dihydrogen phosphate,and initial pH of 8.Under the optimum fermentation condition of A1 B2 C2 D3,the maximum enzyme activity of the mutant RYXP-3 reached 56.1 U/mL.The mutant strain of RYXP-3 could be used as an alternative resource strain for the development of the production of“fengdan”.