桑椹果酒酵母的诱变选育研究

Mutation breeding of wine yeast for mulberry wine

将筛选到的一株桑椹果酒酵母进行单倍体细胞的制取,分别将不同浓度的菌悬液先后经紫外辐照和微波处理,根据平板计数法确定两种诱变因素下出发菌液的最佳的稀释浓度,利用致死率和正变率两个参数来描述诱变选育模型的最佳剂量及诱变时机,然后对出发菌株先进行紫外辐照,再对紫外辐照选育的性状较好的菌株采取微波处理,利用三级筛选模式从大量的平板中筛选具有酿造桑椹果酒的优良酵母。结果表明,紫外辐照20～40s内将会获得较好诱变结果(正变率31.1%～41.2%),而微波处理15s会取得理想诱变结果(正变率22.1%),增大剂量能使得正变率增加,但同时也增大了菌种死亡的风险。筛选到的ME44菌株在2周发酵周期内酒精体积分数为11.7%(v/v),比出发菌株提高7%以上,而且菌株在起酵时间及果酒品质方面都有提高。

Prepared the monolploid cell suspension of Yll yeast strain which screened specially for mulberry wine making, then dealt the suspension with ultraviolet radiation and microwave treatment, and further decided the optimal dilution concentration in two mutagenesis factor by flat plated counting method. Described the optimal dose and mutagenized time of mutagenesis model by fatal rate and positive rate. First treated the start strain with ultraviolet radiation, then selected the perferable property strain for microwave treatment. Applied three-class mode for screening excellent yeast strain for mulberry wine making from large quantity flat plates. The results showed that ultraviolet radiation in 2040s could obtain better mutagene effect （positive between 31.1%-41.2%）, on the other hand, microwave treatment within 15s will be better （positive 22.1%）. Enhanced mutagensis dose may increased the positive, but the risk of death increased at the same time. The ME44 strain in 2weeks fermentation cycle could obtain 11.7%（v/v） alcohol concentration which enhancede 7% to start strain, and fenmentaUon starting time and wine character enhancede simultaneity.