Document 82v633grMywE2yyZda2DQVonZ

Oxidation of Polychlorinated Biphenyls by Achromobacter pGB It M. Ahhcb1 tad 0.0. Focht D*p*rtm*nt / Soil Scimc* and AfricuUurnI SnfinmtriM* Umimrnitr / CalijonU, RivtrtuU, CmUj, Polychlorinated biphenyls (PCSe) have been used extensively in various ccnroerclal products since the 1920's. The widespread ooourrence of these chemicals has been documented by Risebrough et al. (2). Debits the extensive usage of PCBs, data pertalnlnc to the longevity of these chemicals In soil and water are un available. We had reported previously that certain mono and dichlnrinated biphenyls were degraded readily by a species of Achromobacter pCB isolated from sewage effluent (1). It is the intention of this investigation to study the biodegradation of other isomers of PCBs with 2 to 5 chlorine atcans. MATERIALS AND HEIHCOS The following chemicals were purchased from Analabe, Inc., North Haven, Connecticut: 2,3-dlchlaroblpheryl (2,3-DCB), 2.4- diahloroblphenyl (2,4-OCB), 34-dichlorobiphenyl (3,4-DCB), 3.5- dichlcrobiphenyl (3,5-DCB), 33'-dichlorobiphenyl (3,3'-DCB), 3,4,2'-trlohlarobiphenyl (3,4,2*-tCB), 2,3,2*,3'-tetrachlaroblpfaenyl (2,3,2\3,-TC8). 2,5,3',^'-tetrachlorobiphenyl (2,5,3',4'TEB) and 2,3,4,5,6-pentachloroblphenyl (2,3,4,5,6-FCB). Resting cell suspensions of Achrcmobacter pCB grown on PHShlcroblphenyl (pCB) ware tested far their ability to metabo lize 2,3-DCB, 2,4-OCB, 3,4-DCB, 3,5-DCB, 3,3'-DCB, 3,4,2'-tCB, 2*3,2*2,5,3',4'-TCB, and 2,3.4,5,6-PCB. Cultural, --rewilrtn. and analytical techniques used In this study have bean described previously. (1). RESUMES AND DISCUSSION Msncnetrlo studies Indicated that with the exception of 2*5*3',4*J1CB, all the above listed PCBs ware oxidized by bacteria grown on pC8. Accept far a brief lag observed In the degradation at 3,3'-DC, all other PCBs were oxidized without lag. The results are given In Plgares 1 and 2. The manometrlc data also Mflpasted that 2,3-DCB, 2,4-OCB, 3,4-DCB, 3,5-DCB, and 3,5-DCB ten oxidized to an appreciable extent by pure cultures of Achromobacter pCB; 3,4,2*-tCB, 2,3,2',3'-TCB and 2,3.4,5,6-PCB iwre oxidised only slightly. The hlgi degree of oxidation of dftohlorlnated biphenyls in which one of the biphenyl rings was I! Present address: Department of Health, 313 North Plgieroa, Los Angeles, California 90012 91 ftAnlt d lifNMwMil CiMMiMiha A Tutidiff, MsliMi l&mm*^*w**M*- DSW 032781 STLCOPCB4016743 Figure 1- Oxidation of (Uchloroblphenyla. o OJ sJ Go M STLCOPCB4016744 unsubetltuted nay be due to the preferential degrolatlon of the unsubstltuted ring as noted by the extent of oxidation between 3,3*-DCB and all other dLlehlarohlphenyla having one unsubetltuted ring. Even 2,3,4,5,6-PCB was oxidized caiparably to 2,3,2',3'-'ICB and mors than 2,5,3'4'/flCB. The Warburg flask contents were withdrawn upon conpletlon of the experiments--as determined by the return of respiration rate to that of endogenous--and centrifuged to obtain clear supernatant solutions. The supernatant solutions were assayed for liberation of chloride and were analyzed.spectrophotonetrlcally to obtain absorption maxima of products that might have accumulated during degradation. The absorption maxima of the substrates and the Intermediates are shown in Table 1. TABLE 1 Oxygen uptake and absorption maxima (x max) of substrates and products Substrata Oxygen uptake? X max of substrate X max of products 2,W>lohlcroblphvl 2,4-Olchloroblphany1 3 .M&chlcaroblphenyl 3,5-Dichlarobiphenyl 3,3 '-Olchlcrobiphonyl 3, ^, 2'-TWchlaroblphanyl 2,3,2*,3'-Tetrachloro- biphenyl 2,5,3' ,4'-Tetrachlcro- biphenyl 2,3,4,5,6-Pentachloro- biphenyl 2.25 2.25 3.40 2.75 1.60 1.00 0.5 0 0.5 265 235 265 235 265 290*, 280, 235 265 290, 280*, 235 265 400, 235 265 400, 290, 235 265 320, 280 265 " 265 265 280 hanoles oxygendanoles substrate shoulder only - Imsnuch as the bacterium was unable to dehalogenate any of the chlorinated biphenyls, &s noted by the absence of chloride In all supernatants, it appears likely that increasing chlorine substitution renders the biphenyl molecule more resistant to taloroblal attack as the manometrlo results further Indicate. REFERENCES (1) AWED, N., and FOCHT, D. D., Can. J. Microbiol. (In Press). (2) RISEEROUGIH, R.V., RELCHE, P., PEAKAIL, D.B., HERSMAN, S.G., and IQHVEN, M.H. Nature 220, 1098 (1968). n DSW 032783 STLCOPCB4016745