Lactic acid production by Lactobacillus plantarum L10 in a cell-retention continuous culture under different cultivation strategies

The aim of this study was to evaluate the production of lactic acid in two different cell-retention continuous systems using Lactobacillus plantarum L10. This microorganism was cultured in synthetic medium under different cultivation strategies, temperatures (30 and 37 °C), medium composition and glucose concentration in the feeding medium (20, 40 and 80 g/L), at different dilution rates. Lactic acid's yields and productivity were improved differently in both systems operating at different cultivation conditions. In one system name, 92.75 ± 0.18 % high yield values were obtained at low cultivation temperature, low dilution rates (0.21 h-1) and low glucose concentration in the feeding medium. In the other, a high productivity of 14.42 ± 0.08 g/L•h was attained, correlating to high dilution rates (0.48 h-1), cultivation temperature and glucose concentration in the feeding medium, respectively. Production of the L(+)-isomer of lactic acid was influenced by cultivation temperature while yeast extract concentration had a negligible effect. The results of this study can be used to optimize the production of L(+)-lactic acid in Lactobacillus plantarum cultures.