Combination of Cell Growth Dependent and Independent Modes for Efficient L-Lactic Acid Production by Lactobacillus paracasei

In this study,on the basis of L-lactic acid production by Lactobacillus paracasei,a high cell density strategy with the combination of cell growth dependent and independent modes was developed through investigating the optimal initial glucose concentration and the metabolic capacity of resting cells. The results indicated that the cells grew well under 140 g/L of initial glucose concentration,and all the glucose could be rapidly exhausted to produce L-lactic acid. Moreover,the cells could still maintain high metabolic activity within 6~7 h after the end of fermentation. Finally,based on the above results,the L-lactic acid productivity of high cell density phase was enhanced by 1.4-fold compared with that of normal batch fermentation,and the L-lactic acid yield was also improved significantly to 0.985 g/g. This study extended the highly efficient production period so as to improve the production efficiency of L-lactic acid. Otherwise,the auxiliary time required in the fermentation process could be effectively reduced,including seed preparation and cell growth. Thus,it would be potentially applied for future industrial lactic acid production.