Abstract

Background: Acetyl-CoA is a fundamental metabolite in Escherichia coli, and also a precursor for biosynthesis of chemicals and materials suitable for multiple applications. The acetyl-CoA synthesis route from glucose presents low atomic economy due to the release of CO₂ in pyruvate decarboxylation reaction. Because ethanol and acetate, both ordinary and inexpensive chemicals, can be converted into acetyl-CoA directly, they could be alternative substrates for production of acetyl-CoA derivatives.

Results: In this study, the bifunctional reductase AdhE mutant (A267T/E568K), which converts ethanol into acetyl-CoA, was used to enable E. coli to grow on ethanol, and AMP-forming acetyl-CoA synthetase ACS was employed to enhance the ability of E. coli to utilize acetate. Several products derived from acetyl-CoA, including polyhydroxybutyrate, 3-hydroxypropionate, and phloroglucinol, were produced from glucose, ethanol, and acetate, respectively, by engineered E. coli strains. Compared with glucose and acetate, the strains grown on ethanol presented the highest production and yield of carbon source, and metabolome analysis revealed the reasons of high yield from ethanol.

Conclusions: The conversion of ethanol into acetyl-CoA presents high atomic economy along with generation of reducing power, and the yield of target chemical from ethanol is much higher than those from glucose and acetate. All these results suggested that ethanol could be a suitable carbon source for production of acetyl-CoA derived bioproducts.

Fig. Production of acetyl-CoA from various carbon resource. (A) Different metabolic routes for acetyl-CoA production from glucose, acetate or ethanol. The solid lines represent single step, and dotted line represent multiple steps. (B) Comparison of these pathways.

论文链接： Sun SM, Ding YM, Liu M, Xian M, Zhao G*. Comparison of glucose, acetate and ethanol as carbon resource for production of poly(3-hydroxybutyrate) and other acetyl-CoA derivatives. Front Bioeng Biotechnol, 2020, 8:33. DOI:10.3389/fbioe.2020.00833