Abstract: To increase the proliferation concentration of Lactobacillus plantarum(L.plantarum), the effects of different nitrogen sources, buffer salts, different concentrations of manganese sulfate and growth-promoting substances were studied. The results showed that yeast extract was the most suitable nitrogen source for L.plantarum. While buffer salt had no effect on the growth of the strain under pH-controlled condition. The concentration of manganese sulfate was positively correlated with the viable cell count that the strain could reach. No other growth-promoting substances was needed for the culture of L.plantarum when yeast extract was used as nitrogen source. The optimum pH and carbon-nitrogen ratio of the strain were further optimized. Based on the osmotic pressure that could be tolerated by the strain, the medium and process conditions for the culture with pH-controlled and the culture with automatic feedback feeding method were optimized to obtain the optimal culture strategy. The optimum concentration of nitrogen source and manganese sulfate for the three L.plantarum strains were 40-45 g/L and 0.25 g/L, respectively. The optimum carbon-nitrogen ratio was the mass ratio of carbon source and nitrogen source consumed when the growth rate of L.plantarum was inhibited. The viable count of L.plantarum X1 reached 4.1×1010 CFU/mL when pH-controlled 5.5 using the automatic feedback feeding method. The viable count of L.plantarum N8 reached 2.9×1010 CFU/mL using batch culture at pH 5.5. The viable count of L.plantarum N9 reached 6.2×1010 CFU/mL using batch culture with pH-controlled 6.0. The application of this research could significantly improve the industrial production efficiency of L.plantarum.
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