Possibility of teaching Bacillus subtilis ethylene glycol utilization

Teaching a microorganism to use a new substrate necessitates constructing a utilization pathway that connects the substrate to a metabolite in central carbon metabolism. The process is not straightforward and fraught with hiccups such as lack of carbon flux to make a firm connection to central carbon metabolism. Ethylene glycol is one promising alternative substrate given its availability as hydrolysis product from polyethylene terephthalate (PET) plastic waste recycling. But, what is lacking thus far is a utilization pathway that could mediate its transformation into a metabolite that could plug into central carbon metabolism and activate cell growth. This write-up attempts to review prior work on developing ethylene glycol as an alternative feedstock for a bioeconomy as well as origins of ethylene glycol role as a sole carbon source for some microorganisms. While focus is inevitably on developing a “plug-in” pathway for connecting ethylene glycol to central carbon metabolism, preliminary work in this endeavor also needs to focus on understanding any possible metabolic deficiency in the chosen microbial chassis that could make substrate utilization metabolic engineering that much tougher.