谷氨酸棒杆菌S9114中amn基因缺失对生理代谢的影响

Effect of amn gene deletion on Corynebacterium glutamicum S9114 metabolism

摘要:

摘要:【目的】为了研究腺苷单磷酸核苷酶基因(amn)缺失对谷氨酸棒杆菌S9114生理代谢的影响。【方法】本文构建了amn基因缺失菌株△amn，并对谷氨酸发酵性能以及酸耐受性进行了比对分析。【结果】与野生菌株WT相比，amn基因缺失菌株:(1)细胞干重提高了16.2%，谷氨酸产量降低了58.8%;(2)发酵10 h、25 h和40 h，胞内ATP分别提高了3.0、3.7和2.2倍，异柠檬酸裂合酶活性提高17.1%、4.9%和44.5%，异柠檬酸脱氢酶活性降低76.9%、74.6%和5.0%，谷氨酸脱氢酶活性降低42.4%、50.8%和42.4%;(3)pH4.0条件下存活率降低了64.9%，而胞内ROS和蛋白质羰基化水平提高了31.5%和22.5%。【讨论】amn基因的缺失提高了菌株的胞内ATP水平和生物量，但是对谷氨酸发酵和酸性条件的耐受性却产生不利影响。

Abstract:

Abstract:［Objective］ To study the effect of adenosine monophosphate nucleosidase gene deletion on Corynebacterium glutamicum S9114 metabolism.［Methods］ We constructed the amn deficient strain △amn and studied its glutamate fermentation and acid tolerance.［Results］Compared with the wild type strain，biomass of △amn strain increased by 16.2% whereas glutamate production reduced by 58.8%. After 10，25 and 40 h，intracellular ATP level of △amn strain increased 3.0，3.7 and 2.2 times．The isocitrate lyase activity increased by 17.1%，4.9% and 44.5% ，the isocitrate dehydrogenase activity decreased by 76.9%，74.6% and 5.0%，and the glutamate dehydrogenase activity decreased by 42.4%，50.8% and 42.4%．At pH4.0，the survival of △amn strain dropped 64.9%．However，the intracellular ROS and protein carbonylation level showed an increase of 31.5% and 22. 5% respectively.［Conclusion］Knocking out of amn gene enhanced intracellular ATP level and biomass formation，whereas had negative effect on glutamate fermentation and acid tolerance．