Biosynthesis of ethylene glycol in Escherichia coli.

Huaiwei Liu, Kristine Rose M Ramos, Kris Niño G Valdehuesa, Grace M Nisola, Won-Keun Lee, Wook-Jin Chung

Energy and Environment Fusion Technology Center (E2FTC), Department of Energy Science and Technology (DEST), Myongji University, Room 8807, Engineering College Building 2, San 38-2, Namdong, Cheoin-gu, Yongin, Gyeonggi 449-728, South Korea. huaiwei.liu@gmail.com

Applied microbiology and biotechnology 2013 Apr

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Ethylene glycol (EG) is an important platform chemical with steadily expanding global demand. Its commercial production is currently limited to fossil resources; no biosynthesis route has been delineated. Herein, a biosynthesis route for EG production from D-xylose is reported. This route consists of four steps: D-xylose → D-xylonate → 2-dehydro-3-deoxy-D-pentonate → glycoaldehyde → EG. Respective enzymes, D-xylose dehydrogenase, D-xylonate dehydratase, 2-dehydro-3-deoxy-D-pentonate aldolase, and glycoaldehyde reductase, were assembled. The route was implemented in a metabolically engineered Escherichia coli, in which the D-xylose → D-xylulose reaction was prevented by disrupting the D-xylose isomerase gene. The most efficient construct produced 11.7 g L(-1) of EG from 40.0 g L(-1) of D-xylose. Glycolate is a carbon-competing by-product during EG production in E. coli; blockage of glycoaldehyde → glycolate reaction was also performed by disrupting the gene encoding aldehyde dehydrogenase, but from this approach, EG productivity was not improved but rather led to D-xylonate accumulation. To channel more carbon flux towards EG than the glycolate pathway, further systematic metabolic engineering and fermentation optimization studies are still required to improve EG productivity.

Citation

Huaiwei Liu, Kristine Rose M Ramos, Kris Niño G Valdehuesa, Grace M Nisola, Won-Keun Lee, Wook-Jin Chung. Biosynthesis of ethylene glycol in Escherichia coli. Applied microbiology and biotechnology. 2013 Apr;97(8):3409-17