Enhanced hydrogen production from glucose using ldh- and frd-inactivated Escherichiacoli strains
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- Yoshida, A., Nishimura, T., Kawaguchi, H. et al. Appl Microbiol Biotechnol (2006) 73: 67. doi:10.1007/s00253-006-0456-9
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We improved the hydrogen yield from glucose using a genetically modified Escherichia coli. E. coli strain SR15 (ΔldhA, ΔfrdBC), in which glucose metabolism was directed to pyruvate formate lyase (PFL), was constructed. The hydrogen yield of wild-type strain of 1.08 mol/mol glucose, was enhanced to 1.82 mol/mol glucose in strain SR15. This figure is greater than 90 % of the theoretical hydrogen yield of facultative anaerobes (2.0 mol/mol glucose). Moreover, the specific hydrogen production rate of strain SR15 (13.4 mmol h−1 g−1 dry cell) was 1.4-fold higher than that of wild-type strain. In addition, the volumetric hydrogen production rate increased using the process where cells behaved as an effective catalyst. At 94.3 g dry cell/l, a productivity of 793 mmol h−1 l−1 (20.2 l h−1 l−1 at 37 °C) was achieved using SR15. The reported productivity substantially surpasses that of conventional biological hydrogen production processes and can be a trigger for practical applications.