title: Acetate consumption activity directly determines the level of acetate accumulation during Escherichia coli W3110 growth.
abstract: Escherichia coli excretes acetate during aerobic growth on glycolytic carbon sources, which has been explained as an overflow metabolism when the carbon flux into the cell exceeds the capacity of central metabolic pathways. Nonacetogenic growth of E. coli on gluconeogenic carbon sources like succinate or in carbon-limited slow growth conditions is believed an evidence for the explanation. However, we found that a strain defected in the acs (acetyl Co-A synthetase) gene, the product of which is involved in scavenging acetate, accumulated acetate even in succinate medium and in carbon-limited low growth rate condition, where as its isogenic parental strain did not. The acs promoter was inducible in noncatabolite repression condition, whereas the expression of the ackA-pta operon encoding acetate kinase and phosphotransacetylase for acetate synthesis was constitutive. Results in this study suggest that E. coli excretes and scavenges acetate simultaneously in the carbon-limited low growth condition and in nonacetogenic carbon source, and the activity of the acetate consumption pathway directly affects the accumulation level of acetate in the culture broth.
authors.affiliation: CJ Cheiljedang R&D Center for Bioproducts, Seoul , Korea.
authors.forename: Sooan
authors.initials: S
authors.lastname: Shin
authors.forename: Dong-Eun
authors.initials: DE
authors.lastname: Chang
authors.forename: Jae Gu
authors.initials: JG
authors.lastname: Pan
mesh_terms: D000106:Acetate-CoA Ligase / Q000235:genetics / Q000378:metabolism; D000085:Acetates / Q000378:metabolism*; D001692:Biological Transport; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D009154:Mutation
chemical_list: D000085:Acetates; D029968:Escherichia coli Proteins; D000106:Acetate-CoA Ligase