Bacterial Degradation of a Mixture of Hydroxy and Methoxy Polychlorinated Biphenyls

An attempt was made to combine the chemical functionalization of a mixture of polychlorinated biphenyls giving a mixture of hydroxy and methoxy chlorinated biphenyls with the bacterial transformation of the obtained compounds for their disposal was investigated. The reaction of the Sovol mixture with MeONa in MeOH and DMSO with 100% conversion gave a mixture of compounds identified as methoxy (30 compounds), hydroxy (44 compounds), and methoxy(hydroxy) (47 compounds) derivatives of PCB congeners. The total content of all hydroxy derivatives was 77.2%. The Rhodococcus wratislaviensis KT112-7 strain was found to degrade 73–93% of this mixture at the starting concentration of 0.25–1.50 g/L. The best result was obtained upon the degradation of a 0.1 g/L mixture of methoxy and hydroxy polychlorobiphenyls (no starting compounds remained on the 10th day). The specific degradation rate was directly correlated with the initial concentration of the mixture. It was shown that the bacterial transformation does not lead to accumulation of toxic intermediates.