Biodegradation of UV-irradiated polychlorinated biphenyls in surfactant micelles

摘要

Potential enhancement of biodegradability of commercial polychlorinated biphenyls (PCBs) mediated by photodechlorination was investigated. Used in tandem, photolysis and biodegradation of Aroclor 1242 (MW=260), a commercial PCB mixture, dissolved in micellar solution of a nonionic surfactant, polyoxyethylene 10 lauryl ether (POL(10)), was studied. A mixed population of two genetically engineered microorganisms (GEMs), Pseudomonas putida IPL5::TnPCB and Ralstonia eutropha B30P4::TnPCB, was used for the aerobic biodegradation of POL (10) while cometabolizing Aroclor 1242. W-irradiation at 254 nm for 40 minutes caused 63% degradation of Aroclor 1242 in a solution containing 210 mg/L of PCB congeners in 4 g/L POL(10). In the same period, 42% of the PCB chlorine appeared as chloride in solution. Gas chromatograms of UV-irradiated Aroclor 1242 solutions indicated that almost all biorecalcitrant PCB congeners, especially the highly chlorinated ones, were photolyzed. PCB GEMs removed an additional 30 mg/L (14.3%) of the PCBs in 96 hr from the W-irradiated micellar PCB solution. Seemingly, the products of photolysis did not inhibit biodegradation of the remaining congeners or the surfactant. (C) 1998 Published by Elsevier Science Ltd. All rights reserved. [References: 16]