(160an) Bioconversion of Formic Acid in Escherichia coli Using a 2-Hydroxyacyl-CoA Lyase (HACL)-Based Pathway

The effect of greenhouse gas CO2 on climate change has brought intensive research interests on utilization of one-carbon (C1) intermediates produced from the abiotic reduction of CO2, including formic acid and methanol. Here, we used an HACL-based pathway1 to investigate the co-utilization of formic acid and aldehydes by introducing formic acid activation enzymes (FAE), which convert formic acid to formyl-CoA. The HACL-based pathway is a short, linear pathway simpler than other native and engineered routes used for C1 utilization and is also orthogonal to the host metabolic network. The FAEs, including formyl-CoA transferase, acyl-CoA synthase, and acyl-CoA ligase, were initially screened in growing cell cultures using acetone as the carbonyl-containing co-substrate. The utilization of formic acid was further confirmed by analyzing condensation product glycolate and CoA thioester intermediates formyl-CoA and glycolyl-CoA using in vitro assays with purified enzymes. The best performance was achieved when sodium formate and formaldehyde were used as C1 substrates. Product synthesis was also observed when sodium formate was used as the sole carbon source, including the important industrial product ethylene glycol.

1. Chou, A., Clomburg, J.M., Qian, Gonzalez, R.. (2019) Nat Chem Biol 15, 900-906.