耐酸性布拉氏酵母的筛选及高密度培养条件优化

Screening of an acid-resistant Saccharomyces boulardii and optimization of its high density cultivation conditions

布拉氏酵母菌(Saccharomyces boulardii)是临床上作为益生菌药物治疗肠道疾病使用的唯一一株酵母菌,作为微生态制剂,要保证其生物效果,必须能够在胃肠道中保持一定的活菌数,研究发现影响布拉氏酵母菌在胃肠道中存活的最主要因素是低p H,为提高布拉氏酵母菌在低p H条件下的存活率,该研究采用常压室温等离子体(ARTP)诱变技术对S.boulardii进行诱变,最终筛选出3株对低p H值耐受性较好的突变株。对突变株耐低p H稳定性的研究结果表明,在传代20次后,突变株YB-3具有较好的遗传稳定性,其存活率为51.79%。在5 L发酵罐中,对突变株YB-3高密度培养条件进行优化,最终所得布拉氏酵母菌体干质量为58.79 g/L,比原始菌株提高了55.52%。

Saccharomyces boulardii is the only strain of yeast as clinical probiotic drugs for the treatment of intestinal diseases. As a microecology preparation, in order to ensure its biological effect, it must be able to maintain a certain number of viable bacteria in the gastrointestinal tract. Re- search showed that low pH was the most important factor affecting S. boulardii survival rate in the gastrointestinal tract. To improve the survival rate of S. boulardii in low pH condition, atmospheric and room temperature plasma （ARTP） was used for S. boulardii mutagenesis. Finally, three mutant stains with thelow pH-resistant were selected. The results of stability of the mutant strains resistant to low pH showed that after 20 times generation, mutant YB-3 had good genetic stability and its survival rate was 51.79%. In 5 L fermentor, the high density cultivation conditions of mutant YB-3 were optimized. The dry cell weight ofS. boulardii obtained was 58.79 g/L, which was increased by 55.52% than that of the original strain.