富含核糖核酸酿酒酵母的选育及其高密度发酵工艺

Breeding and high density fermentation technology of Saccharomyces cerevisiae with high RNA content

该研究首先以酿酒酵母(Saccharomyces cerevisiae)J-5为出发菌株进行诱变选育,筛选出一株核糖核酸(RNA)含量优于菌株J-5的诱变菌株J-5-9,其RNA含量在摇瓶中达到了13.12%,比出发菌株提高了10.62%。选取糖蜜为碳源,应用正交试验优化菌株J-5-9发酵培养基组成为:糖蜜3%,酵母浸粉2%,磷酸二氢钾0.01%,谷氨酸钠0.2%,硫酸亚铁0.1%。最后利用优化发酵培养基和碳源、氮源和磷源的流加补料工艺,在10 L发酵罐中培养诱变菌株J-5-9,RNA含量达到8.11%,比优化前提高了18.22%,同时细胞生物量达到188 g/L(湿质量),实现了酿酒酵母高产RNA的高密度发酵。这说明诱变菌株J-5-9是一株很有潜力的工业化生产菌株。

Saccharomyces cerevisiae J-5 was used as original strain for mutation breeding. A mutant strain J-5-9 which RNA content was higher than that of strain J-5 was selected. RNA content in shake flask was up to 13.12%, which was 10.62% higher than that in original strain. With molasses as carbon source, by orthogonal experiments, the fermentation medium components were optimized. The optimum conditions were molasses 3%, yeast extract 2%, KH2PO4 0.01%, monosodium glutamate 0.2%, ferrous sulfate 0.1%. Under the conditions, the mutant strain J-5-9 was cultured in the 10 L fermentation tank by fed-batch technology, the RNA content reached 8.11%, which increased 18.22% than that before optimization. The wet cell mass was up to 188 g/L, which achieved high-density fermentation of S. cerevisiae with high RNA production. It indicated that mutant strain J-5-9 was a promising strain for industrial production.