Clean Energy Technology Development: Hydrogen Production by Escherichia coli During Glycerol Fermentation

Abstract

Hydrogen (H2) is accepted as a clean, effective, and renewable energy source; the biotechnology of its production is intensively developed. Glycerol can serve as a cheap carbon source to produce H2 and the other biofuel by Escherichia coli during mixed acid fermentation. Data on metabolic pathways of glycerol fermentation, hydrogenase enzymes responsible for H2 production, and dependence of H2 production on pH and other external factors during glycerol fermentation are summarized; some novel findings are presented. Metabolic engineering to enhance H2 yield from glycerol has resulted in effective strains. The mixed carbon (glycerol and glucose) fermentation is a novel approach to improve H2 production and to enlarge carbon sources containing wastes used: glycerol added to glucose-containing medium is shown to increase H2 production. Taken together these are of significance for improving H2 production biotechnology as clean energy technology.