l-lactic acid production by Lactobacillus casei fermentation using different fed-batch feeding strategies

In this paper, the l-lactic acid production by Lactobacillus casei fermentation using different fed-batch feeding strategies was studied. The effects of different fed-batch methods such as pulse fed-batch, constant feed rate fed-batch, constant residual glucose concentration fed-batch and exponential fed-batch on the fermentation of l-lactic acid were determined. According to the results of experiments, exponential fed-batch culture is an effective method for the fermentation of l-lactic acid. The maximum lactic acid concentration (210 g l−1) and l-lactic acid concentration (180 g l−1) in exponential feeding glucose solution (850 g l−1) and yeast extract (1%) was obtained, respectively. l-lactic acid yield, the maximal dry cell weight and productivity were up to 90.3%, 4.30 g l−1, 2.14 g l−1 h−1, respectively. Comparing with the traditional batch culture, the exponential feeding glucose and yeast extract culture showed 56.5% improvement in l-lactic acid production, 68.6% improvement in dry cell weight and 59.7% improvement in productivity, respectively.