摘要
采用紫外诱变和硫酸二乙酯（DES）诱变剂对产凝乳酶的枯草芽孢杆菌JAASB进行诱变选育，在酪蛋白平板上以凝乳圈直径与菌落直径的比值为指标进行初筛，在液态发酵培养基上进行复筛，选育到三株具有遗传稳定性的高产菌株JAASB－3、JAASB－5、JAASB－14，其凝乳活力分别为1142．6Su，mL、1263．2SU／mL、1333．3SU／mL，比出发菌株分别提高了52％、68％、78％。
The starting strain Bacillus subtilis JAASB producing ehymosin was mutated by UV and DES. Effect of mutation was determined by preliminary screening based on the ratio between milk-clotting zone and colony diameter, and secondary screening based on liquid fermentation. Three mutant strains with good genetic stability and high chymosin activity were obtained. The chymosin activity produced by JAASB-3 ,JAASB-5 and JAASB-14 was 1142.6S U/mL,1263.2 SU/mL,1333.3 SU/mL, respectively.Comparing with the starting strain, chymosin activity produced by JAASB-3 ,JAASB-5 and JAASB-14 was increased by 52%,68% and 78%, respectively.
基金
现代农业产业技术体系建设专项资金资助（CARS-37）.
