红曲霉固态发酵产糖化酶及酸性蛋白酶条件的优化

Optimization of Fermentation Conditions of Glucoamylase and Acid Protease Production with Monascus in Solid-state Fermentation

从8株红曲霉中筛选出红曲霉MQ7作为高产糖化酶和酸性蛋白酶的供试菌株,采用固态发酵方法测定在不同发酵温度、底物料液比、大米和麸皮比例条件下的产酶情况.利用正交实验优化固态发酵产酶过程,确定该菌株产酶最佳发酵条件为:发酵温度30,℃,底物料液比(g∶mL)20∶25,大米麸皮比例(g∶g)17∶3.在此条件下,糖化酶活力达1,641.69,U/g,酸性蛋白酶活力达151.09,U/g.同时研究了NaCl含量对红曲霉酶活力的抑制作用,当NaCl质量分数达到18.92%时,红曲霉MQ7产糖化酶活力下降64.8%,酸性蛋白酶活力下降85.6%.

Monascus MQ7 strain was obtained from eight Monascus strains as the highly glucuoamylase and acid protease producing strain. The solid-state fermentation conditions for the glucoamylase and acid protease production with Monascus MQ7 were studied. Based on single factor tests,in different fermentation temperature,substrate solid-liquid ratio,proportion of rice and bran,the glucoamylase and acid protease production conditions were optimized with L9（34）orthogonal test. The results are as follows：the fermentation temperature is 30,℃,substrate solid-liquid ratio（g∶mL）20∶25,and the proportion of rice to bran（g∶g）17∶3. Under the above conditions,the glucoamylase activity reached 1,641.69,U/g,and the highest acid protease activity reached 151.09,U/g. The inhibition of NaCl on enzyme activity was also verified. When the NaCl mass fraction reached 18.92%,Monascus MQ7,glucoamylase activity decreased 64.8%,and acid protease activity decreased 85.6%.