Development of glycerol-utilizing Escherichia coli strain for the production of bioethanol

• Five ethanol-producing Enterobacter aerogenes gene sets were overexpressed in E. coli BL21 (DE3).
• Glycerol was used as a carbon source by E. coli BL21 (DE3) to produce bioethanol.
• The pEB recombinant E. coli BL21 (DE3) strain produced two-fold more bioethanol than the wild-type strain.
• Increase in bioethanol production was related to an increase in hydrogen production.

The production of bioethanol was studied using recombinant Escherichia coli with glycerol as a carbon source. Glycerol is an attractive feedstock for biofuels production since it is generated as a major byproduct in biodiesel industry; therefore, we investigated the conversion of glycerol to bioethanol using E. coli BL21 (DE3) which harbors several genes in ethanol production pathway of Enterobacter aerogenes KCTC 2190. Fermentation was carried out at 34 °C for 42 h, pH 7.6, using defined production medium. Under optimal conditions, bioethanol production by the recombinant E. coli BL21 (DE3), strain pEB, was two-fold (3.01 g/L) greater than that (1.45 g/L) by the wild-type counterpart. The results obtained in this study will provide valuable guidelines for engineering bioethanol producers.