一株产低温脂肪酶酵母菌的鉴定及酶学性质

Identification of a cold-adapted lipase-producing yeast and its enzyme characterization

低温脂肪酶已成为工业低温工艺良好候选物,在生物质能源、食品、皮制品、废水处理等领域发挥重要作用。本文从实验室保藏的55株产低温脂肪酶酵母菌株中筛选出一株高产菌株NYNU 19160,通过形态学、生理生化以及ITS和26S rDNA序列分析,将该菌株鉴定为Papiliotrema fonsecae。经过硫酸铵分级沉淀、透析、浓缩将该脂肪酶纯化后,对酶学性质进行了研究。结果表明,该脂肪酶最适反应温度为20℃,最适作用pH为7.5,属于低温碱性脂肪酶;Cu显著促进该酶的水解活性,而Li~+表现为显著抑制作用;有机溶剂乙腈、甲醇、乙酸对酶活性有较强的促进作用,而苯和正己烷则抑制了该酶的活性;该酶对对硝基苯酚丁酸脂(pNPC)底物表现出较强特异性。

The cold-adapted lipase, which has become a good candidate for industrial low-temperature processes, plays an important role in the fields of biomass energy, food, leather products and wastewater treatment. In this study, a high-yielding strain, NYNU 19160, was screened from 55 cold-adapted lipase-producing yeast strains preserved in our laboratory. The strain NYNU 19160 was identified as Papiliotrema fonsecae by morphology, physiological characteristics and ITS and 26S rDNA sequence analysis. The properties of the cold-adapted lipase were studied after purification by ammonium sulphate fractionation, dialysis and concentration. Results showed that it belonged to low temperature alkaline lipase. The optimal reaction temperature of the lipase was 20℃, and the optimal reaction pH was 7.5. Cusignificantly promoted the hydrolysis activity of the enzyme, while Lishowed significant indigenous inhibition. Organic solvents, including acetonitrile, methanol and acetic acid, had a great promotion effect on the enzyme activity, while benzene and n-hexane inhibited the enzyme activity. The enzyme showed strong specificity for p-nitrophenyl butyrate(pNPC) substrate.