Biodegradation of chlorpyrifos and 3,5,6-trichloro-2-pyridinol by a newly isolated Paracoccus sp. strain TRP

A bacterium, isolated from activated sludge and named strain TRP, could biodegrade chlorpyrifos and 3,5,6-trichloro-2-pyridinol. Phenotypic features, physiological and chemotaxonomic characteristics, and phylogenetic analysis of 16S rRNA sequence revealed that the isolate belongs to the genus of Paracoccus. Strain TRP could also degrade pyridine, methyl parathion and carbonfuran when provided as sole carbon and energy sources. Native-PAGE and enzymatic degradation assay of the cell-free extracts indicated that an alternative degradation mechanism might involve an inducible enzyme. Degradation study of chlorpyrifos by strain TRP was examined by GC–MS and HPLC; no persistent accumulated metabolite was observed. To the best of our knowledge, this is the first report of a bacterium that could completely mineralize chlorpyrifos. This isolate will be potentially useful in biotreatment of wastewaters and bioremediation of contaminated soils.