1,3,5-TRIHYDROXYBENZENE BIODEGRADATION BY RHODOCOCCUS-SP BPG-8

The metabolic pathway used by Rhodococcus sp. BPG-8 isolated from oil-rich soil in Newfoundland for the degradation of 1,3,5-trihydroxybenzene (phloroglucinol) as a sole source of carbon and energy was determined. Culture filtrates of cells grown on phloroglucinol detected 1,2,3,5-tetrahydroxybenzene when extracted and analyzed using gas chromatography - mass spectrometry, thin-layer chromatography, and ultraviolet spectrophotometry. Nonaromatics were either derivatized with 2,4-dinitrophenylhydrazine and compared against authentic standards by the above methods, or detected by chemical and enzymatic methods. Extracts of cells grown on phloroglucinol contained phloroglucinol hydroxylase activity, and a dioxygenase that carried out ortho-cleavage of 1,2,3,5-tetrahydroxybenzene. The extract also showed inducible activity for further metabolism of acetopyruvate leading to accumulation of formate in the supernatant. A tentative degradative pathway for phloroglucinol by Rhodococcus sp. BPG-8 is proposed.