产脂肪酶菌株的筛选、鉴定以及酶学性质的研究

【目的】筛选高产脂肪酶菌株并鉴定其种属,研究脂肪酶的酶学性质.【方法】以橄榄油为唯一碳源对富含油污土壤中产脂肪酶微生物进行富集培养,用中性红平板进行初筛,结合改进铜皂分光光度计法测定酶活力;对筛选的高产脂肪酶菌株进行形态学观察和相关生理生化实验,再结合16S rDNA序列分析确定其种属;确定该菌株所产脂肪酶的最适作用温度和pH值,并研究金属离子、有机溶剂以及表面活性剂对酶活的影响.【结果】筛选得到一株高产脂肪酶菌株LZ-5,其所产脂肪酶的酶活力为4.78 U/mL;菌种鉴定为表皮葡萄球菌(Staphylococcus epidermidis).该酶最适作用温度为40℃,最适pH值为9.0;Ca~(2+)、Mg~(2+)对酶活力有促进作用,Fe~(2+)、Zn~(2+)、EDTA、SDS、甲醇和乙醇对酶活力有抑制作用,对Na~+、K~+、丙三醇的耐受力较高.【结论】成功分离一株表皮葡萄球菌高产脂肪酶菌株.

Screening and identification on lipase producing microbial and its enzymatic properties

Objective] To screen and identify lipase producing strain,determine the biology activity of the enzyme produced by the strain.Method] Lipase producing microbial in oil-rich soil were cultured in neutral red oil medium with olive oil as the sole carbon source for initial screening,the improved copper soap-photometric method was used for secondary screening;the species of the lipase producing strain was identified by morphological observation,physiology biochemistry and 16S rDNA sequence analysis;activity of the lipase was determined by improved copper soap-photometric method.Effect of metal ion,organic solvent and surfactant was assayed on activity of lipase Result] A lipase producing strain was screened,named as LZ-5.16S rDNA sequence analysis indicated that the strain belong to Staphylococcus epidermidis.The activity of lipase produced by the strain was 4.78 U/mL.The optimum pH and temperature of the lipase were 9.0 and 40 ℃.Lipase activity was stimulated by Ca2+,Mg2+ and inhibited by Fe2+,Zn2+,EDTA,SDS,methyl alcohol and ethyl alcohol.The lipase showed better tolerance to glycerol,Na+,and K+.Conclusion] The strain LZ-5 shows a better lipase activity.