地衣芽孢杆菌LCB-8的紫外诱变及优良菌株的选育

目的]对地衣芽孢杆菌LCB-8进行紫外诱变,以提高其产淀粉酶、蛋白酶和纤维素酶的能力。方法]利用紫外线进行诱变,并对诱变株淀粉酶、蛋白酶和纤维素酶的活力进行定性和定量测定。结果]当紫外诱变的时间为30 s时,菌落的致死率达72.4%,因此紫外线照射诱变最佳时间为30 s。经初筛和复筛,得到2株较好的诱变株。其中,DY-97的淀粉酶活提高150%,蛋白酶活提高78%,纤维素酶活提高17%;DY-34的纤维素酶活提高31%,淀粉酶活提高46%,蛋白酶活提高64%。结论]通过诱变筛选得到的DY-97可用于含蛋白质和淀粉较多的饲料发酵,而DY-34可用于含纤维素较多的饲料发酵。

Ultraviolet Mutagenesis of Bacillus licheniformis LCB-8 and Screening of High-yielding Strain

Objective] To enhance amylase,protease and cellulase activities of Bacillus licheniformis LCB-8 by ultraviolet mutagenesis.Method] Ultraviolet light was used to mutate this strain.The activities of amylase,protease and cellulase were determined to get high-yielding strains.Result] The best time for ultraviolet mutation was 30 s,and the mortality rate reached 72.4%.After primary screening and rescreening,two better strains were obtained.After mutagenesis,the activities of amylase,protease and cellulase of DY-97 strain were enhanced by 150%,78% and 17% respectively.After mutagenesis,the activities of cellulase,amylase and protease of DY-34 strain were enhanced by 31%,46% and 64% respectively.Conclusion] The DY-97 strain is suitable for fermentation of feed rich in protein and amylum,whereas the DY-34 strain is suitable for fermentation of feed rich in cellulose.