title: Inactivation of the Escherichia coli K-12 twin-arginine translocation system promotes increased hydrogen production.
abstract: The effect of deleting the genes encoding the twin-arginine translocation (Tat) system on H2 production by Escherichia coli strain MC4100 and its formate hydrogenlyase upregulated mutant (DeltahycA) was investigated. H2 evolution tests using two mutant strains defective in Tat transport (DeltatatC and DeltatatA-E) showed that the rate doubled from 0.88+/-0.28 mL H2 mg dry weight-1 L culture-1 in the parental strain, to 1.70+/-0.15 and 1.75+/-0.18 mL H2 mg dry weight-1 L culture-1, respectively, in the DeltatatC and DeltatatA-E strains. This increase was comparable to that of a previously characterized hydrogen over-producing E. coli strain carrying a DeltahycA allele. Construction of a tatC, DeltahycA double deletion strain did not increase hydrogen production further. Inactivation of the Tat system prevents correct assembly of the uptake hydrogenases and formate dehydrogenases in the cytoplasmic membrane and it is postulated that the subsequent loss of basal levels of respiratory-linked hydrogen and formate oxidation accounts for the observed increases in formate-dependent hydrogen evolution.
authors.affiliation: School of Biosciences, University of Birmingham, Edgbaston, Birmingham, UK.
authors.forename: David W
authors.initials: DW
authors.lastname: Penfold
authors.forename: Frank
authors.initials: F
authors.lastname: Sargent
authors.forename: Lynne E
authors.initials: LE
authors.lastname: Macaskie
mesh_terms: D003470:Culture Media; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D005560:Formate Dehydrogenases / Q000378:metabolism; D017353:Gene Deletion; D006859:Hydrogen / Q000378:metabolism*; D006864:Hydrogenase / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D009097:Multienzyme Complexes / Q000378:metabolism
chemical_list: D003470:Culture Media; D029968:Escherichia coli Proteins; D026901:Membrane Transport Proteins; D009097:Multienzyme Complexes; C408585:twin-arginine translocase complex, E coli; D006859:Hydrogen; D006864:Hydrogenase; D005560:Formate Dehydrogenases; C054017:formate hydrogenlyase