Degradation of 3-phenylbutyric acid by Pseudomonas sp.
Pseudomonas sp. isolated by selective culture with 3-phenylbutyrate (3-PB) as the sole carbon source metabolized the compound through two different pathways by initial oxidation of the benzene ring and by initial oxidation of the side chain. During early exponential growth, a catechol substance identified as 3-(2,3-dihydroxyphenyl)butyrate (2,3-DHPB) and its meta-cleavage product 2-hydroxy-7-methyl-6-oxononadioic-2,4-dienoic acid were produced. These products disappeared during late exponential growth, and considerable amounts of 2,3-DHPB reacted to form brownish polymeric substances. The catechol intermediate 2,3-DHPB could not be isolated, but cell-free extracts were able only to oxidize 3-(2,3-dihydroxyphenyl)propionate of all dihydroxy aromatic acids tested. Moreover, a reaction product caused by dehydration of 2,3-DHPB on silica gel was isolated and identified by spectral analysis as (--)-8-hydroxy-4-methyl-3,4-dihydrocoumarin. 3-Phenylpropionate and a hydroxycinnamate were found in supernatants of cultures grown on 3-PB; phenylacetate and benzoate were found in supernatants of cultures grown on 3-phenylpropionate; and phenylacetate was found in cultures grown on cinnamate. Cells grown on 3-PB rapidly oxidized 3-phenylpropionate, cinnamate, catechol, and 3-(2,3-dihydroxyphenyl)propionate, whereas 2-phenylpropionate, 2,3-dihydroxycinnamate, benzoate, phenylacetate, and salicylate were oxidized at much slower rates. Phenylsuccinate was not utilized for growth nor was it oxidized by washed cell suspensions grown on 3-PB. However, dual axenic cultures of Pseudomonas acidovorans and Klebsiella pneumoniae, which could not grow on phenylsuccinate alone, could grow syntrophically and produced the same metabolites found during catabolism of 3-PB by Pseudomonas sp. Washed cell suspensions of dual axenic cultures also immediately oxidized phenylsuccinate, 3-phenylpropionate, cinnamate, phenylacetate, and benzoate.
D050548:Catechol 1,2-Dioxygenase; D003374:Coumarins / Q000032:analysis / Q000378:metabolism; D049308:Dioxygenases; D010084:Oxidation-Reduction; D010101:Oxygen Consumption; D010105:Oxygenases / Q000378:metabolism; D010654:Phenylbutyrates / Q000378:metabolism*; D010666:Phenylpropionates / Q000378:metabolism; D011549:Pseudomonas / Q000254:growth & development / Q000378:metabolism*; D013386:Succinates / Q000378:metabolism
D003374:Coumarins; D010654:Phenylbutyrates; D010666:Phenylpropionates; D013386:Succinates; C036032:3-phenylbutyric acid; C017625:2-phenylsuccinate; C036031:3-(2,3-dihydroxyphenyl)butyric acid; C036030:8-hydroxy-4-methyl-3,4-dihydroxycoumarin; D010105:Oxygenases; D049308:Dioxygenases; D050548:Catechol 1,2-Dioxygenase