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.%研究了在谷氨酸发酵产酸期分别添加NaHCO3、调节pH及两者耦联操作条件下的发酵性能.结果表明:只有在升高pH值、添加NaHCO3同时进行或先升高pH值后添加NaHCO3的情况下,葡萄糖消耗量大幅下降,谷氨酸得率显著提高,分别比对照提高36％和34％,且谷氨酸产量可以达到正常水平(75 g/L以上).酶学代谢分析表明,仅仅提高丙酮酸羧化酶活性不能提高谷氨酸得率,只有各个关键酶相互协调配合,即适度弱化丙酮酸脱氢酶和α-酮戊二酸脱氢酶活性的同时,适度提高丙酮酸羧化酶和异柠檬酸脱氢酶活性,才能有效提高谷氨酸发酵整体性能.
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