一株许氏平鲉(Sebastes schlegelii)肠道乳酸菌的分离鉴定及特性分析

To screen wide-spectrum bacteriostatic activity for probiotics application, a lactic acid bacteria strain Weissella cibaria YH1 was recognized among 35 bacterial strains isolated from the intestine of wild Sebastes schlegelii. Morphological observation, physiological and biochemical characteristic analyses, and 16S rDNA sequencing were applied. Skim milk was fermented into coagulation with this gram-positive YH1 without bubbling, and the supernatant was acidic. The effects of pH, temperature, and NaCl content on the growth of strain YH1 were analyzed. Some indicator pathogens (Staphylococcus aureus, Aeromonas hydrophila, Vibrio alginolyticus, Vibrio Parahaemolyticus, Edwardsiella tarda, Vibrio anguillarum, Pseudoalteromonas sp, and Vibrio harveyi) were used to measure the bacteriostatic activity of the strain product in agar diffusion method. Meanwhile, animal safety of strain YH1 was tested by intramuscular and intraperitoneal injections to S. schlegelii. Results show that YH1 can survive in range of pH 5.7-8.8 and 20-40ºC, and best at 7.2-8.4 and 35ºC. The growth of YH1 was inhibited by adding NaCl to MRS medium. The agar diffusion assay revealed that the product of YH1 inhibited the growth of all the indicator pathogens mentioned above. YH1 was safe to S. schlegelii as the survival rate post-injection reached 100%. Therefore, YH1 could inhibit the growth of wide-spectrum bacteria, and shall be developed for more applications in aquaculture.