Mutants of Pseudomonas cepacia G4 defective in catabolism of aromatic compounds and trichloroethylene.
Pseudomonas cepacia G4 possesses a novel pathway of toluene catabolism that is shown to be responsible for the degradation of trichloroethylene (TCE). This pathway involves conversion of toluene via o-cresol to 3-methylcatechol. In order to determine the enzyme of toluene degradation that is responsible for TCE degradation, chemically induced mutants, blocked in the toluene ortho-monooxygenase (TOM) pathway of G4, were examined. Mutants of the phenotypic class designated TOM A- were all defective in their ability to oxidize toluene, o-cresol, m-cresol, and phenol, suggesting that a single enzyme is responsible for conversion of these compounds to their hydroxylated products (3-methylcatechol from toluene, o-cresol, and m-cresol and catechol from phenol) in the wild type. Mutants of this class did not degrade TCE. Two other mutant classes which were blocked in toluene catabolism, TOM B-, which lacked catechol-2,3-dioxygenase, and TOM C-, which lacked 2-hydroxy-6-oxoheptadienoic acid hydrolase activity, were fully capable of TCE degradation. Therefore, TCE degradation is directly associated with the monooxygenation capability responsible for toluene, cresol, and phenol hydroxylation.
Shields
M S
MS
Technical Resources Inc., Gulf Breeze, Florida.
Montgomery
S O
SO
Cuskey
S M
SM
Chapman
P J
PJ
Pritchard
P H
PH
D002396:Catechols / Q000378:metabolism; D003408:Cresols / Q000378:metabolism; D015394:Molecular Structure; D009154:Mutation; D010101:Oxygen Consumption; D010105:Oxygenases / Q000378:metabolism; D010636:Phenols / Q000378:metabolism; D011549:Pseudomonas / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D014050:Toluene / Q000378:metabolism*; D014241:Trichloroethylene / Q000378:metabolism*
D002396:Catechols; D003408:Cresols; D010636:Phenols; C031136:3-methylcatechol; D014241:Trichloroethylene; D014050:Toluene; D010105:Oxygenases; C034047:2-cresol