Current state and perspectives in hydrogen production by Escherichia coli: roles of hydrogenases in glucose or glycerol metabolism.

Escherichia coli has been a robust host strain for much biological research, in particular, research in metabolic engineering, protein engineering, and heterologous gene expression. In this mini review, to understand bacterial hydrogen production by E. coli, the effect of glucose and glycerol metabolism on hydrogen production is compared, and the current approaches to enhance hydrogen production from glycerol as a substrate are reviewed. In addition, the argument from past to present on the functions of E. coli hydrogenases, hydrogenase 1, hydrogenase 2, hydrogenase 3, and hydrogenase 4 is summarized. Furthermore, based on the literature that the E. coli formate-hydrogen lyase is essential for bacterial hydrogen production via recombinant hydrogenases, research achievements from the past regarding heterologous production of hydrogenase are rethought.