A Bacterial Treatment System for the Remediation of Trichloroethylene.
Final rept. 1 Nov 92-31 Dec 94,
UNIVERSITY OF WEST FLORIDA PENSACOLA
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14. Abstract A genetically altered bacterium Burkholderia Pseudomonas cepacia PR123 and closely related genetic derivatives were tested for bioreactor and in situ trichloroethylene TOE degradation. PRi 23 was shown to degrade TOE in a plugged flow bioreactor, but failed to form a stable biofilm under test conditions at Hanscom AFB. Indigenous microorganisms dominated the reactors shortly after inoculation in every instance, despite changes in support matrix and primary carbon source. The continuous addition of the genetically altered bacterium did achieve a significant 80 removal of TOE and cis-dichloroethylene from the waste stream at concentrations of 500-800 ugiL, at 0.26 GPM, thus confirming the capacity the constitutively expressed toluene ortho-monooxygenase Tom to cooxidize TOE under environmental conditions. For this reason the Tom constitutive plasmid TOM31c a kanamycin resistant derivative of TOM, was transferred to two superior biofilm forming bacteria P. capacia 17616 and P. sp JSl5O, and dominant aquifer bacterium from Wichita KS WS23. These transconjugants also constitutively degraded TOE, but were no more competitive in biofilm reactors than PR123. In column tests 95 of the TOE was degraded in an 8 hour residence time.
- Organic Chemistry