Project Summary (2000-2006)

The broad objective of this project is to advance the knowledge of fundamental processes involved in sequential anaerobic and aerobic PCB degradation. This interdisciplinary research will yield biotechnology based on sequential anaerobic-aerobic degradation and mineralization of a wide range of PCBs; applications of these tools will therefore be capable of reducing the biological activity and toxicity of one of the most ubiquitous and troublesome Superfund pollutants. Specific aims are: (1) evaluation of the effect of FeSO4 on and enhancement of dechlorination of Aroclors and sediment associated PCBs by mixed cultures and enrichments; (2) evaluation of metabolic fate and toxicity of PCB intermediates; (3) enhancement of recombinant degradative pathways for ortho-substituted PCBs.; and (4) elucidation of the composition and dynamics of mixed microbial populations involved in PCB degradation and manage combinations of populations for enhanced bioremediation. These efforts will enable more complete dechlorination of PCB mixtures by increasing susceptibility to aerobic metabolism. To further develop the aerobic phase of PCB bioremediation, recently engineered recombinant PCB pathways will be enhanced to minimize accumulation of toxic intermediates and for better coordination of participating pathways. A comprehensive study of diversity, dynamics and metabolic shifts within PCB degrading mixed communities will provide knowledge needed to advance understanding of the molecular, population and environmental factors that control the environmental fate of PCBs in Superfund sites.