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Biotechnology and Bioengineering, Vol.99, No.5, 1273-1280, 2008
Biodegradation of PCBs in two-phase partitioning bioreactors following solid extraction from soil
This article demonstrates the feasibility of a novel process concept for the remediation of PCB contaminated soil. I fie proposed process consists of PCB extraction from soil using solid polymer beads, followed by biodegradation of the extracted PCBs in a solid-liquid two-phase partitioning bioreactor (TPPB), where PCBs are delivered from the polymer beads to the degrading organisms. The commercially available thermoplastic polymer Hytrel (TM) was used to extract Aroclor (R) 1242 from contaminated artificial soil in bench scale experiments. Initial PCB contamination levels of 100 and 1,000 mg kg(-1) could be reduced to 32% +/- 1 to 41% +/- 7 of the initial value after 48 h mixing in the presence of a mobilizing agent at polymer-to-sod ratios of 1% (w/w) and 10% (w/w). The decrease of detectable PCBs in the soil was consistent with an increase of PCBs in the polymer beads. It was further shown that Aroclor (R) 1242 could be delivered to the PCB degrading organism Burkholderia xenovorans LB400 in a solid-liquid TPPB via Hytrel (TM) beads. A total of 70 mg Aroclor (R) 1242 could be degraded in a 1 L solid-liquid TPPB within 80 h of operation.
Keywords:polychlorinated biphenyls;Aroclor (R) 1242;bioremediation;brownfields;availability;Burkholderia xenovorans LB400;sequestration;equilibrium partitioning