高产乳酸菌株的筛选、鉴定及发酵条件研究

Screening,identification and fermentation conditions of high yield lactic acid bacteria strains

以西双版纳传统腌制品为研究对象,采用MRS培养基对菌株进行分离和纯化,并通过形态学观察和分子生物学方法进行鉴定.通过溶钙圈法和EDTA滴定法筛选出产乳酸能力强的菌株,并对该菌株的发酵条件进行研究.结果表明,通过筛选试验从腌制品中筛选得到一株高产乳酸的菌株XSBN-4,经鉴定为植物乳杆菌(Lactiplantibacillus plantarum),该菌株最适生长条件为36℃,并且葡萄糖和CaCO 3的添加量应分别低150、20 g/L.产乳酸最佳发酵条件pH为5.5,发酵温度42℃,发酵时间51 h,乳酸浓度为(84.51±1.33)g/L,产率为(4.51±0.06)g/L/h,残糖量为(0.83±0.03)%,糖酸转化率为(84.51±1.33)%.菌株XSBN-4具有较强产乳酸能力,可作为乳酸发酵的候选菌株.

Taking the traditional pickled products of Xishuangbanna as the research object,the strains were isolated and purified by MRS medium,and identified by morphological observation and molecular biology methods.The strains with strong lactic acid production capacity were screened by calcium-soluble circle method and EDTA titration,and the fermentation conditions of the strains were studied.The results showed that a lactic acid-producing strain XSBN-4 was screened from pickled products,which was identified as Lactiplantibacillus plantarum.The optimum growth condition of this strain was 36℃,and the addition of glucose and CaCO 3 should be lower than 150 and 20 g/L,respectively.The optimal fermentation conditions for lactic acid production were pH 5.5,fermentation temperature 42℃,and fermentation time 51 h.The lactic acid concentration was(84.51±1.33)g/L,the average yield was(4.51±0.06)g/L/h,the residual sugar content was(0.83±0.03)%,and the glucose conversion rate was(84.51±1.33)%.The strain XSBN-4 has strong lactic acid production capacity and can be used as a candidate strain for lactic acid fermentation.