Abstract

The activation of alternative respiration with an internal electron acceptor during anaerobic glucose utilization in E. coli strains with impaired fermentation ability has been studied. It was found out that respiration processes utilizing pyruvic acid as an endogenous electron acceptor can markedly contribute to the maintenance of the anaerobic redox balance in E. coli strains deficient in mixed acid fermentation pathways. The sequential inactivation of the pathways of anaerobic dissimilation of pyruvate and impairment of the functionality of the reductive branch of the tricarboxylic acid cycle led to an increase in the contribution (from 11 to 54%) of the respiratory formation of lactic acid and alanine to the biosynthesis of the reduced products of anaerobic glucose utilization by the strains. Analysis of the enantiomeric composition of the lactic acid and alanine secreted by the strains demonstrated that D-lactate dehydrogenase (Dld), L-lactate dehydrogenase (LctD), and D-alanine dehydrogenase (DadA) participated in the biosynthesis of the respective compounds.

中文翻译：

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发酵能力受损的大肠杆菌中厌氧葡萄糖利用过程中内部电子受体的替代呼吸的激活。

摘要

已经研究了在发酵能力受损的大肠杆菌中，厌氧葡萄糖利用过程中利用内部电子受体激活替代呼吸的激活。发现利用丙酮酸作为内源电子受体的呼吸过程可以显着有助于维持大肠杆菌中的厌氧氧化还原平衡。混合酸发酵途径不足的菌株。丙酮酸的厌氧异化途径的顺序失活和三羧酸循环的还原分支功能的损害导致乳酸和丙氨酸的呼吸形成对乳酸的贡献增加（从11％到54％）。菌株厌氧葡萄糖利用量减少产物的生物合成。菌株分泌的乳酸和丙氨酸的对映体组成分析表明，D-乳酸脱氢酶（Dld），L-乳酸脱氢酶（LctD）和D-丙氨酸脱氢酶（DadA）参与了相应化合物的生物合成。