title: Volatile ketone formation in bacteria: release of 3-oxopentanoate by soil pseudomonads during growth on heptanoate.
abstract: During enrichments to search for soil bacteria that form the volatile ketones, acetone and butanone, we isolated pure cultures of Pseudomonas aureofaciens, P. fluorescens, and P. putida that excrete the beta-keto-acid, 3-oxopentanoate (3-OPA), when grown on heptanoic acid as carbon source. Analysis of 3-OPA used enzymatic decarboxylation by acetoacetate decarboxylase to yield butanone, which was detected by headspace gas chromatography. The formation of 3-OPA was strongly dependent on heptanoic acid concentration, the level of oxygen, and the state of growth, and was not seen with even-chain or other odd-chain fatty acids. Uptake of 3-OPA during stationary phase of growth is probably related to polyhydroxyalkanoate (PHA) formation in these isolates. A model for formation and release of 3-OPA is proposed.
authors.affiliation: Department of Chemistry and Biochemistry, Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder, CO 80309-0215, USA.
authors.forename: M G
authors.initials: MG
authors.lastname: Matiasek
authors.forename: K
authors.initials: K
authors.lastname: Choudhury
authors.forename: M
authors.initials: M
authors.lastname: Nemecek-Marshall
authors.forename: R
authors.initials: R
authors.lastname: Fall
mesh_terms: D000096:Acetone / Q000378:metabolism*; D002074:Butanones / Q000378:metabolism*; D002262:Carboxy-Lyases / Q000378:metabolism; D002849:Chromatography, Gas; D006538:Heptanoic Acids / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism; D010421:Pentanoic Acids / Q000378:metabolism*; D011549:Pseudomonas / Q000254:growth & development / Q000378:metabolism*; D012988:Soil Microbiology; D013379:Substrate Specificity
chemical_list: C430524:3-oxopentanoate; D002074:Butanones; D006538:Heptanoic Acids; D010421:Pentanoic Acids; D000096:Acetone; D002262:Carboxy-Lyases; C023743:acetoacetate decarboxylase; D010100:Oxygen