Fatty acid feedstocks enable a highly efficient glyoxylate-TCA cycle for high-yield production of β-alanine  

作　　者：Yingchun Miao Jiao Liu Xuanlin Wang Bo Liu Weifeng Liu Yong Tao 

机构地区：[1]CAS Key Laboratory of Microbial Physiological and Metabolic Engineering,State Key Laboratory of Microbial Resources,Institute of Microbiology,Chinese Academy of Sciences,Beijing,China [2]College of Life Science,University of Chinese Academy of Sciences,Beijing,China [3]Microcyto Co.Ltd.,Beijing,China

出　　处：《mLife》2022年第2期171-182,共12页微生物（英文）

基　　金：National Key Research and Development Project of China(Grant No.2018YFA0901400);National Natural Science Foundation of China(Grant No.32070068).

摘　　要：Metabolic engineering to produce tricarboxylic acid(TCA)cycle-derived chemicals is usually associated with problems of low production yield and impaired cellular metabolism.In this work,we found that fatty acid(FA)feedstocks could enable high-yield production of TCA cycle-derived chemicals,while maintaining an efficient and balanced metabolic flux of the glyoxylate-TCA cycle,which is favorable for both product synthesis and cell growth.Here,we designed a novel synthetic pathway for production of β-alanine,an important TCA cycle-derived product,from FAs with a high theortecial yield of 1.391 g/g.By introducing panD,improving aspA,and knocking out iclR,glyoxylate shunt was highly activated in FAs and the yield of β-alanine reached 0.71 g/g from FAs,much higher than from glucose.Blocking the TCA cycle at icd/sucA/fumAC nodes could increase β-alanine yield in a flask cultivation,but severely reduced cell growth and FA utilization during fed-batch processes.Replenishing oxaloacetate by knocking out aspC and recovering fumAC could restore the growth and lead to a titer of 35.57 g/l.After relieving the oxidative stress caused by FA metabolism,β-alanine production could reach 72.05 g/l with a maximum yield of 1.24 g/g,about 86% of the theoretical yield.Our study thus provides a promising strategy for the production of TCA cycle-derived chemicals.

关 键 词：Β-ALANINE fatty acid feedstocks glyoxylate shunt TCA cycle Escherichia coli 

分 类 号：Q93[生物学—微生物学] TQ317[化学工程—高聚物工业]