Exploring biochemical pathways for mono-ethylene glycol (MEG) synthesis from synthesis gas

Abstract

Mono-ethylene glycol (MEG) is an important petrochemical with widespread use in numerous consumer products. The current industrial MEG-production process relies on non-renewable fossil fuel-based feedstocks, such as petroleum, natural gas, and naphtha; hence, it is useful to explore alternative routes of MEG-synthesis from gases as they might provide a greener and more sustainable alternative to the current production methods. Technologies of synthetic biology and metabolic engineering of microorganisms can be deployed for the expression of new biochemical pathways for MEG-synthesis from gases, provided that such promising alternative routes are first identified. We used the BNICE.ch algorithm to develop novel and previously unknown biological pathways to MEG from synthesis gas by leveraging the Wood-Ljungdahl pathway of carbon fixation of acetogenic bacteria. We developed a set of useful pathway pruning and analysis criteria to systematically assess thousands of pathways generated by BNICE.ch. Published genome-scale models of Moorella thermoacetica and Clostridium ljungdahlii were used to perform the pathway yield calculations and in-depth analyses of seven (7) newly developed biological MEG-producing pathways from gases, including CO, CO, and H. These analyses helped identify not only better candidate pathways, but also superior chassis organisms that can be used for metabolic engineering of the candidate pathways. The pathway generation, pruning, and detailed analysis procedures described in this study can also be used to develop biochemical pathways for other commodity chemicals from gaseous substrates.

Production of C2–C4 diols from renewable bioresources: new metabolic pathways and metabolic engineering strategies

“…Annually, more than 18 million tons of C2–C4 diols are produced from chemical processes using fossil resource as the starting raw material [ 5 , 6 ]. Owing to the diminishing fossil resource, fluctuation of oil prices, and increasing concerns about environmental problems, production of C2–C4 diols from renewable bioresources by environmentally benign biological processes has received significant interest [ 7 , 8 ].…”

Biotechnological production of glycolic acid and ethylene glycol: current state and perspectives

“…These include for example industrial and agricultural waste streams like lignocellulosic sugars or starch from non-edible plants. However, recently pathways for EG production were designed even for gaseous substrates CO 2 , CO and H 2 (Islam et al 2017 ), although these routes have not yet been tested in practice. In practice, the pathway should also produce GA or EG at high theoretical yield.…”

Genes for a Circular and Sustainable Bio-PET Economy

“…The pathway has been artificially reconstituted in E. coli and is also amenable to metabolic engineering efforts to improve production yields. More recent efforts have shown the feasibility of using synthesis gas (syngas) for the production of EG harnessing the Wood-Ljungdahl pathway of carbon fixation present in acetogenic bacterial species such as Moorella thermoacetica and Clostridium ljungdahlii [94]. In another approach, EG was obtained from gaseous alkenes by a strain of E. coli that expresses recombinantly a monooxygenase and an epoxide hydrolase [95].…”