(438a) Novel Acyloin Condensation Reaction Enables One-Carbon Bioconversion

One-carbon compounds, including carbon
dioxide, carbon monoxide, formate, methanol, and methane, are attractive
alternative feedstocks for the chemical industry due to their availability and
sustainability. However, the efficient and economical utilization of these
feedstocks can be challenging for traditional chemical processes due, in part,
to their diffuse nature. As a result, biological processes are gaining
increased attention as alternatives due to safer, milder processing conditions
and potential for scale-down, which may allow for decentralized, distributed
chemical manufacturing that can make better use of these resources (Clomburg et
al., Science 355, 38, 2017: doi: 10.1126/science.aag0804). In order for
this potential to be realized, however, significant advances in the performance
of C1 utilization pathways and microorganisms must be achieved.

In this talk I will discuss our recent
efforts to engineer and implement biological C1 utilization for chemical
production. To address intrinsic limitations of native one-carbon (C1)
biocatalysts, we have discovered that 2-hydroxyacyl-CoA lyase (HACL), an enzyme
involved in α-oxidation, catalyzes the ligation of carbonyl-containing
molecules of different chain lengths with formyl-CoA to produce C1-elongated
2-hydroxyacyl-CoAs. We characterized the first prokaryotic variant of HACL and found
that the use of formyl-CoA as a C1 donor provides kinetic advantages. We
prototype synthetic HACL-based C1-utilizing pathways for the synthesis of
products, including glycolate, ethylene glycol, glycerate, ethanol,
2-hydroxyisobutyrate, and others in cell-free or whole-cell biocatalysis
formats. Our work establishes the potential for biotechnological applications
of HACL, which includes both bioconversion of C1 feedstocks as well as
synthetic methylotrophy and autotrophy.