(505a) Increasing the in Vivo Nadph Availability by Metabolic Engineering in Escherichia Coli

Many industrially valuable compounds require NADPH as cofactor for their synthesis. The restricted availability of this cofactor in the cells limits the production of the compound of interest in bacterial cultures.

In this work we employ a new strategy to increase the in vivo NADH availability. Specifically, we will present the construction and characterization of an Escherichia coli strain where the endogenous gapA gene encoding for a NAD-dependent glyceraldehydes-3-phosphate dehydrogenase (GAPDH) was replaced by the Clostridium acetobutylicum gapC gene encoding for a NADP-dependent GAPDH. Metabolic flux analysis using C-13 labeling experiments showed that the replacement of this essential reaction with a NADP dependent enzyme has significant effect on the pentose pathway.

The effect of replacing a NAD-dependent GAPDH by a NADP-dependent one was further studied using the production of NADPH-dependent synthesis of compounds.