Hydrogen production from glycerol by Escherichia coli and other bacteria: An overview and perspectives

Hydrogen (H2) is a clean, effective and renewable fuel which can be produced by different methods including biological ones, namely fermentation and biophotolysis. To improve fermentative H2 production the strategies, implicating use of by-products, utilization of carbon containing organic wastes and optimization of biotechnology process conditions, are developed. Glycerol, a biodiesel by-product, can serve as a cheap carbon containing source to produce H2 by Escherichia coli. Recent data on metabolic pathways, responsible hydrogenases and dependence of H2 production on external factors during glycerol fermentation are summarized. The strains are constructed to enhance H2 yield. The mixed carbon sources (glycerol and glucose) fermentation is a novel approach: glycerol added to glucose containing medium increases H2 production; different carbon sources comprising wastes can be used. H2 production from glycerol by different bacteria is overviewed; cultures types, new technologies and optimal conditions, purification of H2 and developing bioreactors are highlighted. All of these are significant for further developing H2 production biotechnology from glycerol and perspective for applied energy systems.