【摘要】 从自制的酒酿利用酪蛋白培养基分离纯化到了一株产凝乳酶的微小毛霉菌株(ZZMZ-19),从ZZMZ-19菌株的cDNA文库筛选到了两个凝乳酶基因ch1和ch2并实现了凝乳酶基因ch1和ch2在枯草芽孢杆菌菌株(ZZMZ-01)中的的克隆与表达。ch1和ch2阳性克隆菌株在酪蛋白培养基中发酵30h左右的时间凝乳酶酶活达到最大,分别为48.27SU/mL和41.02SU/mL,相比出发菌株发酵时间缩短了15h。用交联葡聚糖凝胶柱G100分离纯化其发酵上清液后,用十二烷基硫酸钠聚丙烯酰胺凝胶电泳方法测得CHⅡ和CHⅢ分子量分别为32ku和30ku。更多还原

【Abstract】 A high chymosinproducing Mucor pusillus strains(ZZMZ-19) was isolated from home-made Jiu-Niang using casein medium,and two novel chymosin genes ch1 and ch2 were cloned from cDNA library of ZZMZ-19 and expressed in Bacillus subtilis strains(ZZMZ-01).The recombined ZZMZ-01 strain was cultured in the casein medium.The results showed that the maximum activities of recombined chymosin were obtained after 30h fermentation,which was 15h earlier than that of the original strain Mucor pusillus ZZMZ-19.The values were 48.27SU/ml and 41.02SU/ml,respectively.The expressed chymosin were purified using cross-linking glucan gel column and determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis.It was found that the molecular weights of CH1 and CH2 enzymes were 32 ku and 30 ku,respectively.更多还原