高赖氨酸酵母菌的辐照选育

Irradiate Breeding for High Lysine Yeast

采用高能电子束辐照处理四株不同的酵母菌株 ,筛选赖氨酸含量较高的突变株并研究电子束对酵母的辐照效应 .试验表明 :电子束处理酵母的最佳剂量为 4 .14～ 4 .83k Gy,临界致死剂量为6.8k Gy,起始剂量为 0 .69k Gy,不同菌株对电子束的敏感性不同 ,其敏感性强度分别为产朊假丝酵母 >产香酵母 >热带假丝酵母 >面包酵母 .发酵试验表明 :不同剂量的电子束处理酵母 ,其胞外赖氨酸含量都发生不同程度的变异 ;其变异幅度为 84～ 2 90μg/ ml,经电子束处理的酵母其胞外赖氨酸含量比出发菌株赖氨酸含量平均提高 10 .9% .在剂量为 4 .83k Gy,致死率 80 %的条件下 ,酵母胞外赖氨酸变异幅度最广 ,产生高赖氨酸菌株的突变株比例为最大 ,达到 16.5% (胞外赖氨酸含量在 1.4 mg/ ml以上 ) ,在突变体选育方面具有较大的可选择性和可行性 。

Four yeast strains were irradiated with high energy electron dose.Itindicated thatthe best suitable treating dose was4 .14～ 4 .83k Gy,the lethal treating dose was6.8k Gy and the initial treating does0 .69k Gy.The treat- ing sensitivity varied with the differentstrains.After radiant treated with high energy electron,the lysine content of the yeast increased0 .6%～ 2 5.1% ,with an average of10 .9% .When the treating dose was4 .83k Gy and the lethal rate80 % ,the lysine variation was wide spread and the high lysine strains amounted to about16.5% .