Rice bran powder usually contains indigenous microorganisms. However, it is difficult to sterilize completely the microorganisms attached to solid organic matters.Thus we used the defatted rice bran powder without sterilization as an extreme case of insufficient sterilization in SSF. Before the production of D-lactic acid, we examined the effect of indigenous microorganisms in the rice bran on the fermentation without inoculating L. delbrueckiiIFO 3202.Fig. 2shows the formation of
organic acids at pH 6.8 in MRS medium containing the rice bran powder and the mixture of amylase and
cellulase