酱醪中耐盐高产酶菌株的筛选、分离和鉴定及其生化特性分析

Screening,Isolation and Identification of a Salt-Tolerant and Efficient Enzyme-Producing Strain in Sauce Mash and Analysis of Its Biochemical Characteristics

从高盐稀态酱醪中分离筛选高产酶的菌株,首先通过平板溶解圈法初筛,再挑取单菌落到脱脂牛奶平板及淀粉酶平板复筛,然后选择溶解圈较大的菌株进行摇瓶发酵,根据所筛菌株的蛋白酶活力、淀粉酶活力、产酶传代稳定性,综合对比分析后筛选出1株高产蛋白酶及淀粉酶的菌株ST-1,该菌株蛋白酶活力为62.08 U/mL,淀粉酶活力为31.17 U/mL,传代20次后酶活稳定。菌株ST-1的菌落呈乳白色不透明状,表面粗糙,有褶皱,易于挑取,液体培养未产气。镜检结果为革兰氏阳性芽孢杆菌,结合生理生化特征分析及16S rDNA鉴定,菌株ST-1被鉴定为解淀粉芽孢杆菌。

Efficient enzyme-producing strains are isolated and screened from the high-salt liquid sauce mash.Firstly,they are screened by the plate dissolution circle method,and then the single colony is selected and put on the skimmed milk plate and the amylase plate for re-screening.Next,the strains with larger dissolution circles are selected for shaking flask fermentation.According to the protease activity,amylase activity and enzyme generation stability of the screened strains,a efficient protease-and amylase-producing strain ST-1 is screened after comprehensive comparative analysis.The protease activity of the strain is 62.08 U/mL,the amylase activity is 31.17 U/mL,and the enzyme activity is stable after 20 generations.The colony of strain ST-1 is milky white and opaque with rough and wrinkled surface,easy to pick up,and no gas is produced in liquid culture.The microscopy result shows that it is Gram-positive Bacillus.Combined with physiological and biochemical characteristic analysis and 16S rDNA identification,strain ST-1 is identified as Bacillus amyloliquefaciens.