A rotating disk contactor(RDC) was designed to perform L-lactic acid fermentation with a filamentous fungi, Rhizopus oryzae, which was immobilized on the surfaces of the rotating discs. The bioreactor was operated using repeated-batch method as well as continuous feeding method. An anionic resin, D354, slightly basic in nature and of high selectivity and capacity was chosen for lactic acid separation. A coupled process of L-lactic acid fermentation and ion-exchange separation was evaluated experimentally. The results indicated that the pH value of the fermentation broth could be maintained at about 3-3.5 without any addition of alkali. The conversion ratio of glucose to L-lactic acid was about 0.7 g . g(-1) and the fermentation rate reached as high as 62.5 g . h(-1). m(-2).