Abstract:To prepare lyophilized powder of Leuconostoc mesenteroides BD1710 with high bacterial cell survivality，the cultivation conditions were optimized by the response surface methodology.A practice survivality of 92.44%of the bacterial cells of the strain BD1710 was obtained by directly lyophilizing the bacterial culture obtained under the optimized cultivation conditions，which was composed of tomato juice supplemented with 168 g/L sucrose （with the initial pH value of the broth adjusted to 7.3），and cultivation at 29.5℃for 29.5 h，which was in general agreement with the predicted value and significantly higher than of the survivality（76.81%）of the bacterial cells obtained by cultivating the strain BD1710 in M17 after the cells were lyophilized at the same condition.It is postulated the exopolysaccharides synthesized by the strain BD1710 and natural protective agent in the medium provided the predominant cryptoprotection to the bacterial cells during the freezen-drying process.Therefore，the directly freezen-drying the bacterial cells obtained under cultivation conditions provided a simplified method to prepare lyophilized Leuconostoc mesenteroides powder with high bacterial cell survivality.