In this study, a glucose feedback controller had been designed. Under the controller, the glucose concentration in L-lactic acid culture could be automatically controlled at 15 +/- 1 g/L. Furthermore, L-lactic acid production by Lactobacillus rhamnosus LA-04-1 in fed-batch culture was significantly increased to 170 g/L L-lactic acid using the controller compared with 130 g/L L-lactic acid in pulse fed-batch and 135 g/L in L-lactic acid constant feed rate fed-batch cultures. The results showed that the controller was effective at glucose control in L-lactic acid culture. The control strategy could also be used in other fermentation processes.