高产脂肪酶酵母菌株的分离筛选及紫外诱变

Isolation of Lipase Yeast Strains and Their Induction With Ultraviolet Radiation

利用定向分离法从市场购得的苹果、梨、葡萄、面粉、酒糟、啤酒花等6个样品中分离出7株产脂肪酶菌株:曲霉1株,酵母6株.其中从面粉中分离出来的菌株MF具有较高的酶活力,粗酶活力达29.17 U.mL-1,经初步鉴定为假丝酵母(Candida sp.).对该菌株产酶条件进行优化可知:该菌的最佳碳源是1%的10∶1(m/V)的酵母膏+乳化液;最佳氮源为2%的3∶1(m/m)玉米粉+蛋白胨;培养的最适初始pH值为8.0,最佳培养时间为72 h,最适反应温度为40℃,最佳反应时间为30 min.优化后的酶活力达41 U.mL-1,比优化前提高了40.5%.对MF菌株进行初步紫外诱变处理,突变菌株酶活力70.83 U.mL-1,比未处理的菌株的脂肪酶活力提高了105%.

The paper conducted a lipase production experiment which screened out one mold strain and six yeast strains from apple, pear, grape, wheat flour, lees and hops that were bought from the market. The strain （MF）isolated from the flour was identified as Candlda sp. and had higher enzyme activity （29.17 U · mL^-1）. Factors influencing lipase production of MF were studied; results show that the mixture of yeast extracts and emulsion in a ratio of 10：1（m/V） is the best carbon resource, the mixture of corn meal and peptone [3 ： 1 （m/m）] is the best nitrogen resource, the optimum initial pH value is 8. 0, the optimum culture time is 72 hours, the best reaction temperature is 40℃ and the optimum reaction time is 30 min. Induced with ultraviolet radiation, mutants of MF strains were obtained and the enzyme activity from the mutant strains is 70. 83 U ·mL-1, which was increased by 105% compared with the enzyme activity from the original MF strains.