摘要：The aim of this research was to study lactic acid product from glucose by R.oryzae without pH controlling, with pH 5 controlling, pH 6 controlling, andpH 7 controlling. Control of pH was done to avoid the accumulation oforganic acids that could make pH decreasing on fermentation medium. Thisresearch used a treatment medium without pH controlling and threetreatment medium with pH controlling. A treatment medium without pHcontrolling was added by 0.1 g CaCO3 before fermentation while treatmentmedium with pH controlling were added by 5% CaCO3 until pH 5, 6, 7 foreach medium after 24 hours fermentation. Control of pH were done every12 hours during fermentation. Fermentation lasted for 72 hours. Theparametric measurement included glucose analysis, biomass and lactic acidproduct were done at the age of fermentation 24, 36, 48, 60 and 72 hours. Theresults showed that glucose consumption, biomass and lactic acid productwere increased following increasing fermentation age and happened at allof treatment medium. The highest lactic acid product was 35.75 g/L onmedium with pH 6 controlling at 72 hours fermentation, with Yp/s was 0.31and efficiency of lactic acid fermentation was 62%. Lactic acid product onmedium without pH controlling, with pH 5 controlling and with pH 7controlling were 30; 25.45; and 24.70 g/L.
