缺失分枝菌酸层提高谷氨酸棒状杆菌L-谷氨酸产量的研究  

Deletion of Mycolic Acid Layer Increased L-glutamate Production in Corynebacterium glutamicum

作　　者：李贺丹 张德志 赵桂红 李姿含 胡晓清 王小元[1,2] LI Hedan;ZHANG Dezhi;ZHAO Guihong;LI Zihan;HU Xiaoqing;WANG Xiaoyuan(State Key Laboratory of Food Science and Resources,Jiangnan University,Wuxi 214122,China;School of Biotechnology,Jiangnan University,Wuxi 214122,China)

机构地区：[1]江南大学食品科学与资源挖掘全国重点实验室,江苏无锡214122 [2]江南大学生物工程学院,江苏无锡214122

出　　处：《食品与生物技术学报》2024年第8期31-40,共10页Journal of Food Science and Biotechnology

基　　金：国家“十四五”重点研发计划项目(2021YFC2100900)。

摘　　要：谷氨酸棒状杆菌(Corynebacterium glutamicum,C.glutamicum)的分枝菌酸层对维持细胞的通透性有重要作用,但是其合成需要消耗大量的底物和能源。作者通过敲除谷氨酸棒状杆菌ATCC13869中聚酮合酶编码基因pks13,构建了突变菌株Δpks13。与野生型相比,突变菌Δpks13细胞体积变大、形状变圆且细胞壁结合松散容易脱落,但L-谷氨酸产量提高了8倍。薄层层析和液相色谱-质谱联用分析发现,Δpks13菌株细胞壁中的脂质主要为磷脂。实时荧光定量PCR分析发现,与野生型相比,Δpks13谷氨酸外排相关基因mscCG的转录水平上调,而α-酮戊二酸脱氢酶编码基因odhA和下游产物精氨酸合成相关基因(argB、argC、argD、argF、argG、argH、argJ)转录水平下调。这些基因转录水平的改变解释了Δpks13 L-谷氨酸产量提高的机制。The mycolic acid layer in Corynebacterium glutamicum(C.glutamicum)plays important role in maintain cell permeability,however,its synthesis consumes substantial energy and substrate in the synthesis process.A mutant strain,Δpks13,was constructed by deleting the polyketide synthase gene pks13 in C.glutamicum ATCC13869.Compared to the wild type,the mutant strainΔpks13 cells were larger,more rounded,and with a loosely bound cell wall that tended to detach easily,while the L-glutamate yield increased 8-fold.Thin layer chromatography and liquid chromatography mass spectrometry analysis revealed that phospholipids were the primary cell wall lipids inΔpks13.Quantitative real-time PCR analysis revealed that,compared with wild-type strain,the transcript level of the glutamate efflux-related gene mscCG was upregulated,while the transcription levels of theα-ketoglutarate dehydrogenaseencoding gene odhA and the downstream arginine synthesis-related gene(argB,argC,argD,argF,argG,argH and argJ)were downregulated inΔpks13 cells.These changes in genes transcription levels explain the mechanism underlying the enhanced L-glutamate production inΔpks13.

关 键 词：谷氨酸棒状杆菌 分枝菌酸 L-谷氨酸 

分 类 号：TQ922.1[轻工技术与工程—发酵工程] Q78[生物学—分子生物学]