Novel pathway of toluene catabolism in the trichloroethylene-degrading bacterium g4.
o-Cresol and 3-methylcatechol were identified as successive transitory intermediates of toluene catabolism by the trichloroethylene-degrading bacterium G4. The absence of a toluene dihydrodiol intermediate or toluene dioxygenase and toluene dihydrodiol dehydrogenase activities suggested that G4 catabolizes toluene by a unique pathway. Formation of a hybrid species of O- and O-labeled 3-methylcatechol from toluene in an atmosphere of O(2) and O(2) established that G4 catabolizes toluene by successive monooxygenations at the ortho and meta positions. Detection of trace amounts of 4-methylcatechol from toluene catabolism suggested that the initial hydroxylation of toluene was not exclusively at the ortho position. Further catabolism of 3-methylcatechol was found to proceed via catechol-2,3-dioxygenase and hydroxymuconic semialdehyde hydrolase activities.
Shields
M S
MS
Technical Resources Inc. and U.S. Environmental Protection Agency Environmental Research Laboratory, Gulf Breeze, Florida 32561.
Montgomery
S O
SO
Chapman
P J
PJ
Cuskey
S M
SM
Pritchard
P H
PH