Degradation of 1,2-dichlorobenzene by a Pseudomonas sp.
A Pseudomonas sp. that was capable of growth on 1,2-dichlorobenzene (o-DCB) or chlorobenzene as a sole source of carbon and energy was isolated by selective enrichment from activated sludge. The initial steps involved in the degradation of o-DCB were investigated by isolation of metabolites, respirometry, and assay of enzymes in cell extracts. Extracts of o-DCB-grown cells converted radiolabeled o-DCB to 3,4-dichloro-cis-1,2-dihydroxycyclohexa-3,5-diene (o-DCB dihydrodiol). 3,4-Dichlorocatechol and o-DCB dihydrodiol accumulated in culture fluids of cells exposed to o-DCB. The results suggest that o-DCB is initially converted by a dioxygenase to a dihydrodiol, which is converted to 3,4-dichlorocatechol by an NAD+-dependent dehydrogenase. Ring cleavage of 3,4-dichlorocatechol is by a catechol 1,2-oxygenase to form 2,3-dichloro-cis,cis-muconate. Preliminary results indicate that chloride is eliminated during subsequent lactonization of the 2,3-dichloro-cis,cis-muconate, followed by hydrolysis to form 5-chloromaleylacetic acid.
Haigler
B E
BE
Air Force Engineering and Services Center, Tyndall Air Force Base, Florida 32403.
Nishino
S F
SF
Spain
J C
JC
D000429:Alcohol Oxidoreductases / Q000378:metabolism; D001673:Biodegradation, Environmental; D050548:Catechol 1,2-Dioxygenase; D002396:Catechols / Q000378:metabolism; D055598:Chemical Phenomena; D002621:Chemistry; D002712:Chlorides / Q000378:metabolism; D002722:Chlorobenzenes / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D002855:Chromatography, Thin Layer; D049308:Dioxygenases; D008401:Gas Chromatography-Mass Spectrometry; D008298:Maleates / Q000378:metabolism; D010084:Oxidation-Reduction; D010088:Oxidoreductases; D044925:Oxidoreductases Acting on CH-CH Group Donors; D010105:Oxygenases / Q000378:metabolism; D011549:Pseudomonas / Q000201:enzymology / Q000254:growth & development / Q000378:metabolism*; D012722:Sewage
D002396:Catechols; D002712:Chlorides; D002722:Chlorobenzenes; D008298:Maleates; D012722:Sewage; C055405:5-chloromaleylacetic acid; C055404:3,4-dichlorocatechol; C004726:2-dichlorobenzene; D010088:Oxidoreductases; D000429:Alcohol Oxidoreductases; C023125:dihydrodiol dehydrogenases; D010105:Oxygenases; D049308:Dioxygenases; D050548:Catechol 1,2-Dioxygenase; D044925:Oxidoreductases Acting on CH-CH Group Donors; C116788:cis-1,2-dihydro-1,2-dihydroxynaphthalene dehydrogenase