Abstract:One strain of Lactobacillus was isolated from the fermentation broth of traditional fermented grain and identified as Lactobacillus sakei by physiological and biochemical tests，colony and strain morphological observation，and 16S rRNA sequencing.The composition of MRS medium as the basal medium was adjusted with the viable bacterial count as the indicator.On this basis，the medium composition was optimized by response surface methodology. The results showed that the optimal medium was composed of 14.50 g/L fish peptone，6.50 g/L yeast extract powder，28.00 g/L glucose，1.50 g/L ammonium citrate tribasic，2.00 g/L potassium dihydrogen phosphate，0.20 g/L magnesium sulfate，0.12 g/L manganese sulfate，and 1.00 mL/L Tween-80. With this medium，the viable bacterial count reached 3.125×109 CFU/mL，which increased by 1 478.28% compared with that（1.980×108 CFU/mL）in the MRS basal medium.This optimized medium has high viable bacterial count and is easy to prepare and economical，which provides a reference for the industrial culture of L.sakei.