title: Cresol metabolism by the sulfate-reducing bacterium Desulfotomaculum sp. strain Groll.
abstract: The metabolism of cresols under sulfate-reducing conditions was investigated in Desulfotomaculum sp. strain Groll. This strain grows on a variety of aromatic compounds, including para- and meta- but not ortho-cresol. Degradation of p-cresol proceeded by oxidation reactions of the methyl group to yield p-hydroxybenzoate, which was then dehydroxylated to benzoate. The aromatic intermediates expected for this pathway, p-hydroxybenzyl alcohol, p-hydroxybenzaldehyde, p-hydroxybenzoate, and benzoate, were readily metabolized by strain Groll. Utilization of these intermediates generally preceded and inhibited the degradation of p-cresol. p-Hydroxybenzoate and benzoate were detected in culture fluid as metabolites of p-cresol. p-Hydroxybenzaldehyde and p-hydroxybenzoate were detected in cultures degrading p-hydroxybenzyl alcohol. Enzyme activities responsible for utilization of p- and m-cresol, induced by growth on the respective cresol, were detected in cell-free extracts of strain Groll. The compounds detected in culture fluids and the enzyme activities detected in cell-free extracts indicate that the pathways for the degradation of p- and m-cresol converge on benzoate, followed by metabolism to benzoyl-coenzyme A (CoA). Strain Groll can utilize both cresol isomers under sulfate-reducing conditions by similar reactions, but the enzyme activities catalyzing these transformations of the two isomers appear distinct.
authors.affiliation: Department of Botany and Microbiology, University of Oklahoma, Norman 73019, USA.
authors.forename: K L
authors.initials: KL
authors.lastname: Londry
authors.forename: J M
authors.initials: JM
authors.lastname: Suflita
authors.forename: R S
authors.initials: RS
authors.lastname: Tanner
mesh_terms: D000693:Anaerobiosis; D001673:Biodegradation, Environmental; D003066:Coenzyme A Ligases / Q000378:metabolism; D003408:Cresols / Q000378:metabolism*; D016999:Sulfur-Reducing Bacteria / Q000254:growth & development / Q000378:metabolism*
chemical_list: D003408:Cresols; C032538:4-cresol; D003066:Coenzyme A Ligases; C077977:cresol; C042041:3-cresol