镇江香醋醋醅中优势高产酸醋酸菌菌株的筛选

镇江香醋是中国传统发酵香醋之一,具有较高的营养价值。本实验对镇江香醋醋醅中高产酸的优势醋酸菌进行了筛选和分离鉴定。最终分离得到15株产酸菌,通过16S r DNA序列分析,鉴定出8株醋酸菌。8株醋酸菌产酸分析结果表明,醋酸菌D-3-4的产酸量达到60 g/L,为高产酸菌株。对8株醋酸菌进行耐酒精、耐温度、耐乙酸性能测试后发现:在酒精浓度不超过9%时,醋酸菌D-3-4的产酸量最高;当酒精浓度大于9%时,醋酸菌C-3-2-1的产酸量最高,酒精转化率最高;当温度为42℃时,醋酸菌D-3-4和R-4-2仍有30 g/L的产酸量;当乙酸浓度大于30 g/L时,醋酸菌D-3-4与C-3-2-2的产酸量在各菌株中最高;综合各性能比较得出醋酸菌D-3-4性能最优,为优势高产酸醋酸菌。 

Screening of acetic acid bacteria with high yield of acid from vinegar pei of Zhenjiang aromatic vinegar

Zhenjiang aromatic vinegar is traditionally fermented vinegar in China and bears valuable nutritions.In this study,acetic acid bacteria( AAB) with high yield of acetic acid were investigated by screening from vinegar Pei of Zhenjiang aromatic vinegar.Fifteen strains of producing acid bacteria were isolated and eight strains of AAB were identified by 16 S r DNA sequencing analysis.Among these eight strains,strain D-3-4 had a higher ability to produce acetic acid,reaching 60 g/L.The results of resistance testing to alcohol,temperature and acetic acid showed that the strain D-3-4 had the highest yield of acid when alcohol concentration was no more than 9%; but strain C-3-2-1 had the highest yield of acid and a conversion efficiency of alcohol when alcohol concentration was more than 9%.The study of thermo-tolerance demonstrated that strains D-3-4 and R-4-2 still had higher ability to yield acid,reaching 30 g/L at 42 ℃.The experiment of resistance to acetic acid showed strains D-3-4 and C-3-2-2had the highest yield of acid at 30 g/L acetic acid concentration.Totally,the acid production of strain D-3-4 was superior to other strains.Therefore,the strain D-3-4 was finally selected as the dominant AAB of high production.