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 1(-1)) and L-lactic acid concentration (180 g 1(-1)) in exponential feeding glucose solution (850 g 1-1) 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 1(-1), 2.14 g 1(-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. (c) 2006 Elsevier Ltd. All rights reserved.