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Biodegradation of PCBs

Thesis/Dissertation ·
OSTI ID:7281602
PCBs were examined for biodegradability by a strain of Pseudomonas sp. designated E1, by a strain of Pseudomonas aeruginosa designated E2, and by a strain of Pseudomonas putida designated E3. The PCBs included Aroclor mixes from Aroclor 1221 to Aroclor 1268, and pure congeners ranging from monochlorobiphenyl to decachlorobiphenyl. These congeners represented all structural classes. Pure culture studies revealed that cells of E1 grew well on all structural classes of PCB congeners up to heptachlorobiphenyl, and all Aroclor mixes up to Aroclor 1260. Gas chromotographic analysis revealed that biphenyl/acetate grown resting cells of E1 degraded congeners up to octachlorobiphenyl. The degradative patterns for E2 and E3 were assessed using gas chromatographic techniques. E2 was found to be markedly inferior to E1, degrading only the mono-, di-, and tri-chlorobiphenyl tested. Pseudomonas putida strain E3 could not degrade any PCB congener. Mutations in both E2 and E3 that enabled them to utilize more highly chlorinated congeners of PCBs were obtained in nutritionally depleted environments. Such mutants could not be obtained by direct selection using minimal media and appear to be [open quotes]Cairnsian[close quotes] mutations. The Pseudomonas sp. strain E1 was tested in 15 prior or current National Priority List soil microcosms to assess its biodegradative ability in situ. E1 was able to completely degrade the 2,3,4,2[prime],3[prime],4[prime]-2,4,5,2[prime],4[prime],5[prime]-hexachlorobiphenyl congener in seven of the microcosms within two months as well.
Research Organization:
Houston Univ., TX (United States)
OSTI ID:
7281602
Country of Publication:
United States
Language:
English