Hydrogen production by recombinant Escherichia coli strains.

The production of hydrogen via microbial biotechnology is an active field of research. Given its ease of manipulation, the best-studied bacterium Escherichia coli has become a workhorse for enhanced hydrogen production through metabolic engineering, heterologous gene expression, adaptive evolution, and protein engineering. Herein, the utility of E. coli strains to produce hydrogen, via native hydrogenases or heterologous ones, is reviewed. In addition, potential strategies for increasing hydrogen production are outlined and whole-cell systems and cell-free systems are compared.