Fermentation performances under the condition of NaHCO3 supplement and pH regulation during glutamate fermentation were investigated.When pH was raised to 8.0 before or at the same time with adding NaHCO3,comparable glutamate production with control(above 75 g/L) was achieved and the consumption amount of glucose was decreased greatly.And glutamate yield was increased by 36% and 34% respectively.Enzymes metabolic analysis showed that glutamate yield could not be promoted by increase of pyruvate carboxylase activity alone.The overall fermentation performance improvement could be achieved only when pyruvate carboxylase and isocitrate dehydrogenase were stimulated,while α-ketoglutarate dehydrogenase complex and pyruvate dehydrogenase were repressed simultaneously.