硫酸二乙酯、紫外及^γCO60辐射诱变筛选高产丁二酮菌株

Screening of High-Diacetyl-Yield Strains by DES、 UV and ^γCO60 Mutation

以干酪乳杆菌亚种(Lactobacillus casei subsp.casei)ATCC393为出发菌株,其产丁二酮能力为57.31mg/L。分别采用硫酸二乙酯、紫外及γCO60辐射诱变育种,发酵,测丁二酮产量。γCO60辐射诱变后获得2株高产菌株,丁二酮产量分别为79.73mg/L和73.06mg/L,各为出发菌株的1.39倍和1.27倍。γCO60辐射诱变的最佳条件:50Gy/min剂量率,菌液浓度108个/mL,750Gy剂量照射处理。此时致死率为99.36%。

Lactobacillus casei subsp.casei （ATCC393） as starting strains were treated with DES,UV and ^γCO60,and fermented to test production,two high-producing strains were obtained by ^γCO60,diacetyl production were 79.73 mg/L and 73.06 mg/L,the mutant strains＇s productivity were as 1.39 times and 1.27 times much as the starting strains＇,whose production was 57.31 mg/L.The optimum radiation conditions were determined as 50 Gy/min dose rate,with a suspension of 108 cells per mL,750 Gy radiation dose at this time,its mortality was 99.36%.