不同贮存期高温大曲中乳酸菌的多样性及其耐受性分析

该研究对不同贮存期高温大曲中乳酸菌的数量、群落结构与多样性的变化规律进行分析。 结果表明，高温大曲贮存过程中，乳酸 菌的数量由完成制曲时（0 d）的1.7×104 CFU/g增长至30 d时的1.4×105 CFU/g，最终贮存至120 d时乳酸菌数量达到最大值（7.6×105 CFU/g）。 通过高通量测序，从大曲中共鉴定出5个属，分别为乳杆菌属（Lactobacillus）、乳球菌属（Lactococcus）、肠球菌属（Enterococcus）、片球 菌属（Pediococcus）、双歧杆菌属（Bifidobacterium），其中格氏乳球菌（Lactococcus garvieae）在各贮存期30 d、60 d和120 d大曲乳酸菌中 占比最多，分别为66.31%、47.75%和47.18%。 通过富集培养和平板分离，从高温大曲中共分离、鉴定出18株乳酸菌，对其中6株乳酸的 生长曲线、耐温性、耐酸性和耐乙醇能力进行了测定，其中菌株pH4-3能耐受47 ℃高温，菌株JD-1能耐受酒精度8%vol，并且二者均耐 酸（pH 3.5）。

Diversity and tolerance of lactic acid bacteria in high temperature Daqu at different storage periods

The high-temperature Daqu in different storage period was selected as the research object. The changes of the number, community structure and diversity of lactic acid bacteria in high temperature Daqu for different storage periods were analyzed. The results showed that during the storage of high temperature Daqu, the number of lactic acid bacteria increased from 1.7×104 CFU/g (0 d) to 1.4×105 CFU/g (30 d), and then reached the maxi-mum value of 7.6×105 CFU/g (120 d). The results of high-throughput sequencing showed that 5 genera were identified as Lactobacillus, Lactococcus, Enterococcus, Pediococcus and Bifidobacterium. Lactococcus garvieae accounted for the largest proportion of lactic acid bacteria in Daqu with stor- age time of 30 d, 60 d and 120 d, which accounted for 66.31%, 47.75% and 47.18%, respectively. By enrichment culture and plate separation, 18 strains of lactic acid bacteria were isolated and identified. The growth curve, temperature resistance and acid resistance capacities of 6 strains were determined, and results showed that strain pH4-3 can tolerate temperature 47 ℃ , and strain JD-1 can tolerate alcohol content 8% vol, and the two strains were both acid tolerable (pH 3.5).