利用自汾酒大曲中分离获得的产酯能力较高的红曲霉菌株,采用正交试验法,以酯化酶活性为检测指标,优化了发酵培养基配方和培养条件,确定了最佳发酵培养基成分质量配比为麸皮:水=1:1;最佳发酵条件为:红曲霉接种量为1%,发酵温度为30℃,发酵4 d,制得酯化酶酶制剂。在此基础上,采用响应面优化法对其酯化酶的催化条件进行了优化,确定了最佳催化条件为:乙醇和乳酸的摩尔比为6,加酶量1.5%,反应时间60h,反应温度30℃,乳酸乙酯生成量可达到3.38 g/L。

We isolated a new strain-Monascus,from Fen Liquor daqu to produce high yield esters.We used Orthogonal optimization method to optimize the culture medium and culture conditions to obtain maximum esterases activity.The results showed that the optimal medium is bran and water at the ratio of 1∶1.The results also presented that the optimum fermentation conditions as follows: Monascus inoculation is 1%,the fermentation temperature is 30 ℃,the fermentation time is 4d.Based on these findings,we prepared esterases by Monascus.Meanwhile,we utilized the response surface methodology to determine the optimal conditions for catalytic reaction of ethyl lactate.The results showed that the molar ratio of ethanol and lactic acid was 6,the enzyme dosage was 1.5%,the reaction time was 60h,and the reaction temperature was 30 ℃.The yield of ethyl lactate can reach 3.38 g / L.This result can provide some experimental basis to develop the flavoring liquor ethyl lactate.