【摘要】 在利用HPLC分析谷氨酸发酵过程样品时,发现在色谱峰17.5 min处有一未知物质,其UV信号比较强,且与谷氨酸积累相关,通过高压液相和串联质谱,该物质鉴定为N-乙酰-谷氨酰胺。对比分析不同发酵过程,N-乙酰-谷氨酰胺积累与谷氨酸偶联,且与谷氨酸产量呈相关。溶氧对N-乙酰-谷氨酰胺合成没有显著影响,玉米浆是影响其合成的重要因素,随着玉米浆添加量的增加,N-乙酰-谷氨酰胺/谷氨酸比值逐渐降低,当玉米浆添加量大于10 mL/L时,继续添加玉米浆该比值不受影响。更多还原

【Abstract】 By HPLC analysis of samples from glutamic acid fermentations,an unknown chemical was found to accumulate in glutamic acid production at the retention time of 17.5 minute.This chemical was identified as N-acetyl glutamine based on the HPLC-tandem mass spectrometry analysis and approved by using commercial compounds.N-acetyl-glutamine formation was coupled with the glutamic acid production positively and almost linearly with the prolongation of the fermentation processes.Comparative analysis of different fermentation processes revealed that dissolved oxygen had little influence on the accumulation of N-acetyl-glutamine,while the amount of corn steep liquor affected its production dramatically.The ratio of N-acetyl-glutamine / glutamate decreased rapidly with the increase of corn steep liquor addition.But when the corn steep liquor was added more than 10mL/L,the decrease of the ratio became slowly.更多还原