An Engineered E. coli with PPP Cyclization and EDP Enhancement to Increase Biosynthesis

Abstract

Glucose degradation pathways are central metabolism for NAD(P)H, ATP, and bio-production. It is general knowledge that E. coli oxidizes carbohydrates through Embden-Meyerhof-Parnas (EMP) glycolytic pathway. However, it possesses overlooked glycolytic pathway called Entner- Doudoroff (ED) pathway. This alternative pathway is thermodynamically favorable pathway which produces one ATP per glucose but costs less than EMP using fewer enzymatic steps. ED pathway is also metabolic highway by omitting unfavorable reactions. In this poster, we describe EDA50(ED pathway Adaptation 50) which is an engineered strain for ED pathway enhancement. Gene knockout of pfkA/B can block EMP and circulate PP pathway. EDA50 was obtained by evolving E. coli in minimal salt media for 50 days with pfkA/B mutant. During adaptive evolution, there were missense mutations in EDP and PPP related genes. Each mutation has positive effect on ED pathway enhancement with different portion respectively and it makes EDA50 grow more comparing with pfkA/B mutant. Both ED pathway enhancement and cyclization of PPP can increase NADPH synthesis in E. coli, so fatty acid synthesis which requires reductive reaction using NADPH as electron source is accelerated producing long chain fatty acid more about 2 folds.