title: Efficient induction of formate hydrogen lyase of aerobically grown Escherichia coli in a three-step biohydrogen production process.
abstract: 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 (++), DeltahycA) 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 DeltaldhA DeltafrdBC) 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.
authors.affiliation: Microbiology Research Group, Research Institute of Innovative Technology for the Earth, 9-2 Kizugawadai, Soraku-Gun, Kyoto, Japan.
authors.forename: Akihito
authors.initials: A
authors.lastname: Yoshida
authors.forename: Taku
authors.initials: T
authors.lastname: Nishimura
authors.forename: Hideo
authors.initials: H
authors.lastname: Kawaguchi
authors.forename: Masayuki
authors.initials: M
authors.lastname: Inui
authors.forename: Hideaki
authors.initials: H
authors.lastname: Yukawa
mesh_terms: D000332:Aerobiosis; D004790:Enzyme Induction; D004794:Enzyme Repression; D004926:Escherichia coli / Q000201:enzymology* / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000235:genetics; D005560:Formate Dehydrogenases; D005561:Formates; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D006859:Hydrogen / Q000378:metabolism*; D006864:Hydrogenase; D007770:L-Lactate Dehydrogenase / Q000235:genetics; D008190:Lyases / Q000096:biosynthesis*; D009097:Multienzyme Complexes; D016254:Mutagenesis, Insertional; D017064:Process Assessment, Health Care; D021122:Protein Subunits / Q000235:genetics; D013385:Succinate Dehydrogenase / Q000235:genetics
chemical_list: D029968:Escherichia coli Proteins; D005561:Formates; D009097:Multienzyme Complexes; D021122:Protein Subunits; C030544:formic acid; D006859:Hydrogen; D007770:L-Lactate Dehydrogenase; D006864:Hydrogenase; D005560:Formate Dehydrogenases; C054017:formate hydrogenlyase; D013385:Succinate Dehydrogenase; D008190:Lyases