Degradation and O-methylation of chlorinated phenolic compounds by Rhodococcus and Mycobacterium strains.

AUTOR(ES)

Häggblom, M M

RESUMO

Three polychlorophenol-degrading Rhodococcus and Mycobacterium strains were isolated independently from soil contaminated with chlorophenol wood preservative and from sludge of a wastewater treatment facility of a kraft pulp bleaching plant. Rhodococcus sp. strain CG-1 and Mycobacterium sp. strain CG-2, isolated from tetrachloroguaiacol enrichment, and Rhodococcus sp. strain CP-2, isolated from pentachlorophenol enrichment, mineralized pentachlorophenol and degraded several other polychlorinated phenols, guaiacols (2-methoxyphenols), and syringols (2,6-dimethoxyphenols) at micromolar concentrations and were sensitive to the toxic effects of pentachlorophenol. All three strains initiated degradation of the chlorophenols by para-hydroxylation, producing chlorinated para-hydroquinones, which were then further degraded. Parallel to degradation, strains CG-1, CG-2, and CP-2 also O-methylated nearly all chlorinated phenols, guaiacols, syringols, and hydroquinones. O-methylation of chlorophenols was a slow reaction compared with degradation. The preferred substrates of the O-methylating enzyme(s) were those with the hydroxyl group flanked by two chlorine substituents. O-methylation was constitutively expressed, whereas degradation of chlorinated phenolic compounds was inducible.

Documentos Relacionados

• O-Methylation of Chlorinated para-Hydroquinones by Rhodococcus chlorophenolicus
• Bacterial O-methylation of halogen-substituted phenols.
• Bacterial O-Methylation of Chloroguaiacols: Effect of Substrate Concentration, Cell Density, and Growth Conditions
• Metabolism of the herbicide atrazine by Rhodococcus strains.
• Degradation of Phenolic Compounds and Ring Cleavage of Catechol by Phanerochaete chrysosporium