[关键词]
[摘要]
核糖核酸(RNA)是一类非常重要的生物分子,降解后得到的核苷酸、核苷及碱基具有广泛用途。酿酒酵母是目前生产RNA的主要食品级微生物。本研究采用常压室温等离子体(ARTP)技术进行酿酒酵母诱变育种,利用氯化钾敏感性筛选,多次反复诱变最终得到在以糖蜜为碳源的摇瓶试验中RNA含量为112 mg-RNA/g-DCW,提高了39%的突变菌株Y17aM3。经过对Y17aM3培养条件优化后,确定生产RNA最适接种量为10%,最适pH为5.5,最适温度为26 ℃,且传代稳定性良好。研究发现在最佳培养条件下,添加磷酸可使Y17aM3的RNA含量提高至119 mg-RNA/g-DCW;添加蛋白胨可使Y17aM3的RNA含量提高至122 mg-RNA/g-DCW。上述结果不仅证明ARTP诱变育种方法突变效果显著,可应用于工业微生物的选育,而且有助于降低基于核苷酸的食品添加剂的生产成本。
[Key word]
[Abstract]
As an important biomolecule, ribonucleic acid (RNA) can be degraded into nucleotides, nucleosides and bases which exhibit a great potential in wide applications. Saccharomyces cerevisiae is widely used in food industry and generally regarded as safe are the preferred source of nucleic acid. In this study, the cells were repeatedly exposed under atmospheric and room temperature plasma (ARTP), with the aim to screen high-yield nucleic acid strains with potassium chloride sensitivity. A mutant strain Y17aM3 was successfully obtained. In shake flask test with molasses as carbon source, Y17aM3 contained 112 mg-RNA/g-DCW RNA, 39% higher than that of the untreated control. The optimal inoculation quantity of Y17aM3 to produce RNA was 10%.The optimal pH and temperature of fermentation was 5.5 and 26 ℃, respectively. When culturing with optimal condition, it was found that adding phosphoric acid increased RNA content to 119 mg-RNA/g-DCW, and adding peptone increased RNA content to 122 mg-RNA/g-DCW. The results not only demonstrate the effectiveness of using ARTP mutation strategy for the industrial microorganism breeding, but also can greatly reduce the production cost of nucleotide-based food additives.
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[基金项目]
国家自然科学基金青年基金项目(30471225);中央高校基本科研业务费项目(2017MS103)