Isolation and identification of lactic acid bacteria from Tongxian fish in Shangcheng county of Xinyang

In this study, lactic acid bacteria were isolated and purified from Tongxian fish in Shangcheng county of Xinyang fermented for 5 d, 10 d and 15 d by dilution plate method and streak separation method, and lactic acid bacteria with excellent fermentation characteristics were screened by morphological observation and physiological and biochemical tests. The screened strains were identified by molecular biology techniques, and their growth and acid-producing properties were analyzed. The results showed that 19 strains were isolated and purified from fresh fish, 12 of them were lactic acid bacteria, all of which produced no viscosity, fermented glucose, maltose, lactose and sucrose, produced acid without gas, amino acid decarboxylase test results were negative, and could hydrolyze starch, among which strain L15-9 had the strongest starch hydrolysis ability, NaCl tolerance, nitrite tolerance and bacteriostasis ability. The results showed that a total of 19 strains were isolated and purified from Tongxian fish, of which 12 were lactic acid bacteria. All 12 strains did not produce viscosity, fermented glucose, maltose, lactose and sucrose produced acid but no gas. The results of amino acid decarboxylase test were negative, and all strains could hydrolyze starch. Among them, strain L15-9 had the strongest capacity of starch hydrolysis, NaCl resistance, nitrite resistance and antibacterial ability. Strain L15-9 was identified as Lactiplantibacillus plantarum. It rapidly entered a logarithmic growth phase after 2 h and a stable growth phase after 12 h, and its pH decreased to below 4.0 at 12 h.