Efficient induction of formate hydrogen lyase of aerobically grown Escherichia coli in a three-step biohydrogen production process
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A three-step biohydrogen production process characterized by efficient anaerobic induction of the formate hydrogen lyase (FHL) of aerobically grown Escherichia coli was established. Using E. coli strain SR13 (fhlA ++, ΔhycA) at a cell density of 8.2 g/l medium in this process, a specific hydrogen productivity (28.0 ± 5.0 mmol h−1 g−1 dry cell) of one order of magnitude lower than we previously reported was realized after 8 h of anaerobic incubation. The reduced productivity was attributed partly to the inhibitory effects of accumulated metabolites on FHL induction. To avoid this inhibition, strain SR14 (SR13 ΔldhA ΔfrdBC) was constructed and used to the effect that specific hydrogen productivity increased 1.3-fold to 37.4 ± 6.9 mmol h−1 g−1. Furthermore, a maximum hydrogen production rate of 144.2 mmol h−1 g−1 was realized when a metabolite excretion system that achieved a dilution rate of 2.0 h−1 was implemented. These results demonstrate that by avoiding anaerobic cultivation altogether, more economical harvesting of hydrogen-producing cells for use in our biohydrogen process was made possible.
KeywordsHydrogen Production Dilution Rate Biohydrogen Proton Motive Force Sodium Formate
We thank C. A. Omumasaba (Research Institute of Innovative Technology for the Earth) for helpful comments on the manuscript.
- Alam KY, Clark DP (1989) Anaerobic fermentation balance of Escherichia coli as observed by in vivo nuclear magnetic resonance spectroscopy. J Bacteriol 171:6213–6217Google Scholar
- Leonhartsberger S, Korsa I, Böck A (2002) The molecular biology of formate metabolism in enterobacteria. J Mol Microbiol Biotechnol 4:269–276Google Scholar
- Presser KA, Ratkowsky DA, Ross T (1997) Modelling the growth rate of Escherichia coli as a function of pH and lactic acid concentration. Appl Environ Microbiol 63:2355–2360Google Scholar
- Zheng XJ, Yu HQ (2005) Inhibitory effects of butyrate on biological hydrogen production with mixed anaerobic cultures. J Environ Manage 74:65–70Google Scholar