生物加工过程2024，Vol.22Issue(4)：388-394,7.DOI:10.3969/j.issn.1672-3678.2024.04.004
大肠杆菌苹果酸有氧发酵溢出机制的解析及其应用
Mechanism of overflow metabolism and its application for L-malate synthesis
摘要
Abstract
The utilization of renewable biomass to produce L-malic acid,an important C4 dicarboxylic acid,has attracted significant interests in past years.Herein,we investigated the aerobic synthesis of L-malic acid regarding the influence from several key factors including nitrogen limited conditions,temperature,and pH.As a result,nitrogen limited conditions played a pivotal role in the accumulation of L-malic acid.Additionally,the optimal temperature and pH for the synthesis were determined to be 35℃ and 6.8,respectively.Based on the analysis of cofactor concentrations and transcription levels for genes associated with the respiratory chain,the excessive accumulation of L-malic acid might be attributed to the declining efficiency of the electron respiratory chain.In other words,inadequate oxidation of NADH and insufficient availability of NAD+impeded the catalytic conversion of L-malic acid to oxaloacetic acid,leading to the excretion of L-malic acid into the extracellular environment.As the removal of gene ndh in NADH dehydrogenase Ⅱ could decrease the electron respiratory chain efficiency,the recombinant E.coli AFP111(Δndh)exhibited the ability to metabolize a significant quantity of succinic acid,affording L-malic acid as the primary product with a yield of 0.65 g/g under nitrogen sufficient conditions.Our research demonstrated that the respiratory chain modification could enhance the overflow metabolism of intermediate metabolites,offering valuable theoretical support and guidance in this field.关键词
L-苹果酸/溢出代谢/辅因子/NADH脱氢酶/电子呼吸链Key words
L-malic acid/overflowmetabolism/cofactor/NADH dehydrogenase/respiratory chain分类
生物工程引用本文复制引用
王伟,陈持,万屹东,潘春,马江锋..大肠杆菌苹果酸有氧发酵溢出机制的解析及其应用[J].生物加工过程,2024,22(4):388-394,7.基金项目
国家自然科学基金面上项目(22178175) （22178175）
