实验室芽孢杆菌菌种库中高产蛋白酶、糖基转移酶菌株的测定与筛选

该研究以实验室前期构建的小型芽孢杆菌菌种库中的335株芽孢杆菌菌株为研究对象，通过测定其产蛋白酶和糖基转移酶的特性挖掘到蛋白酶缺陷菌株68株、产中性蛋白酶菌株185株、产碱性蛋白酶菌株217株和具较强蛋白分泌能力的菌株87株。经进一步筛选获得22株高产碱性蛋白酶菌株和12株高产中性蛋白酶菌株；另外，基于此菌株资源库，同时进行了产新型糖基转移酶的菌株筛选，以甜菊苷为底物，得到了13株底物转化率达50%以上的菌株，其中菌株BAP#和114#的转化产物分别被鉴定为莱鲍迪苷D和莱鲍迪苷E。综上可见，实验室的芽孢杆菌菌株资源库虽然规模较小，但无论是对于常用工业酶制剂的开发，还是对于新型食品用酶的定向挖掘，都提供了丰富和多样的菌种资源，显示了很好的菌种筛选应用前景。

Determination and screening of high-yield protease and glycosyltransferase strains from Bacillus strains library in laboratory

The protease and glycosyltransferase production properties of 335 Bacillus strains from Bacillus strains library constructed in the early stage of the laboratory were determined, and 68 protease-deficient strains, 185 neutral protease-producing strains, 217 alkaline protease-producing strains and 87 strains with fairly strong protein secretion ability were obtained. Through further screening, 22 strains with high-yield alkaline protease ability and 12 strains with high-yield neutral protease ability were obtained. In addition, the novel glycosyltransferase-producing strains were screened based on the strains library. Using stevioside as substrate, 13 strains with the substrate conversion rate more than 50% were obtained. Among them, the transformation products of strains BAP# and 114# were identified as rebaudioside D and rebaudioside E, respectively. In conclusion, although the Bacillus strains library in the laboratory was small in scale, it provided abundant and diverse strain resources for both the development of common industrial enzyme preparations and the directional mining of new food enzymes, showing a good prospect for the application of strain screening.