Biology of Methanogenesis
Anaerobic Bioremediation

Department of Marine Biotechnology UMBC - Institute of Marine & Environmental Technology


Microbial Reductive Dechlorination of Polychlorinated Biphenyls (PCBs)


 

 

Historically, harbor regions have been heavily impacted by the accumulation of PCBs inadvertently released during naval and industrial activities.  As PCBs are hydrophobic, they strongly associate with organic carbon, clays and silt that settle into the anaerobic regions of marine sediments.  Commercial production of PCBs was banned in the United States in 1978, but recent reports on the distribution of PCBs in marine coastal harbor regions (e.g. Baltimore Harbor, New Bedford Harbor, Charleston Harbor, Newark Bay, and Los Angeles Harbor among others) demonstrate the tenacity of PCB contamination  

Anaerobic dechlorination of polychlorinated biphenyls (PCBs) is a critical step in the biodegradation of highly chlorinated congeners commonly detected in the environment.  Understanding this microbial process is critical for making management decisions concerning both remediation and risk assessment of PCB-impacted coastal regions.  As a result of this ONR funded research, our laboratory and collaborators identified for the first time two PCB dechlorinating microbes and based on this discovery developed molecular ribosomal probe assays, which are currently being optimized for detection of PCB dechlorinating catalysts in selected coastal sediments.  Building on these discoveries we are studying the role of biocatalysis on the fate of PCBs using the following specific approaches: (i) assess the PCB dechlorination potential in situ in un-enriched sediments in the presence of co-contaminants, (ii) identify environmental factors that inhibit or enhance PCB dechlorination, (iii) determine the fate of PCBs in coastal sediments using isotopic analysis.  Results of this study  provide fundamental information on the biocatalytic processes required to develop bioremediation strategies and promote intrinsic PCB transformation in impacted marine harbor sediments and dredge deposition sites.  In addition to implications for biological remediation, the investigations expand our understanding of the organismal and metabolic biocomplexity that is potentially available for dehalogenation processes in coastal sediments.  
 

Collaborators 

     Hal D. May, Ph.D., Medical University of South Carolina 

     Joy Watts, Ph.D., University of Portsmouth

    Christopher M. Reddy, Ph.D., Woods Hole Oceanographic Institution
 

Project Team               

    Sonja Fagervold, Ph.D. 

    Birthe Kjellerup, Ph.D.

   Meredith Wright, Ph.D.

   Nathalie Lombard, Ph.D.

                      

Related Publications and Abstracts

Birthe V. Kjellerup, Piuly Paul, Upal Ghosh, Harold D. May, Kevin R. Sowers. 2012. Aroclor 1260 contaminated soils show spatial variability of dechlorinating bacteria and PCB reducing activities.  Appl. Environ. Soil  Microbiol.  Article ID 584970: 1-11.  [ABSTRACT]

 

Fagervold, Sonja K., Joy E. M. Watts Harold D. May and Kevin R. Sowers.  2011.  Bioaugmentation with dechlorinating microorganisms influences the pathways and rates of PCB dechlorination in sediment microcosms.  Wat. Res.  45: 3899-3907.  [ABSTRACT]

 

Kevin R Sowers, Rayford B. Payne and Harold D May.  Bioaugmentation of PCB impacted sediments with biocatalytic GAC.  Battelle International Symposium on Bioremediation and Sustainable Environmental Technologies.  Reno, Nevada, 27-30 June 2011.

May, H.D., G. S. Miller, B.V. Kjellerup, K.R. Sowers.  2008.  Dehalorespiration with Polychlorinated Biphenyls by an Anaerobic Ultramicrobacterium.  Appl. Environ. Microbiol.  [ABSTRACT]. 

K.R. Sowers.  Finding a Needle in the Microbial Haystack: Identification of the Microbial Catalysts that Dechlorinate Polychlorinated Biphenyls (PCBs).  Working with Extremophiles Workshop.  Annual Meeting of the Society for Industrial Microbiology, Denver, CO. July 29, 2007.

K.R. Sowers*, S.K. Fagervold, B. Kjellerup, G.S. Miller and H.D. May.  Developments in the Anaerobic In Situ Treatment of Polychlorinated Biphenyls (PCBs).  Ninth International In Situ and On-Site Bioremediation Symposium.  May 7-10, 2007.  Baltimore, Maryland.

Kjellerup, B.V., Ghosh, U., Paul, P., May, H., Sowers, K.S.  Abundance and Diversity of Aerobic and Anaerobic PCB degrading Bacteria In Contaminated Soil biofilms.  4th ASM Conference on Biofilms, Quebec City, Quebec, Canada.  March 25 – 29, 2007.

 K.R. Sowers, B. Kjellerup, S.K. Fagervold and H.D. May.   Developments in the anaerobic in situ monitoring and treatment of polychlorinated biphenyls (PCBs) in marine sediments.  8th International Marine Biotechnology Conference, Eilat, Israel.  March 11-16, 2007.

 Fagervold, S.K., H.D. May and K.R. Sowers.  2007.  Microbial reductive dechlorination of Aroclor 1260 in Baltimore Harbor sediment microcosms is catalyzed by three phylotypes within the Chloroflexi.  Appl. Environ. Microbiol.  73: 3009-3018  [ABSTRACT].

H.D. May, L.A. Cutter, G.S. Miller, C.E. Milliken, J.E.M. Watts, and K.R. Sowers.  2006.  Stimulatory and Inhibitory Effects of Organohalides on the Dehalogenating Activities of PCB-Dechlorinating Bacterium o-17.  Environ. Sci Technol. 40: 5704-5709  [ABSTRACT].

Fagervold, S.K., J.E.M. Watts, H.D. May and K.R. Sowers.  2005.  Sequential reductive dechlorination of meta-chlorinated PCB congeners in sediment microcosms by two different phylotypes of Chloroflexi . Appl. Environ. Microbiol. 71: 8085-8090 [ABSTRACT]. 

Watts, J.E.M., S.K. Fagervold, H.D. May and K.R. Sowers.  2005.  A PCR based specific assay reveals a diverse population of bacteria within the Chloroflexi associated with the reductive dehalogenation of polychlorinated biphenyls.  Microbiology UK, 151: 2039-2046 [ABSTRACT].

Miller, G.S., C.E. Milliken, K. R. Sowers, and H. D. May.  2005.  Reductive Dechlorination of Tetrachloroethene to trans-Dichloroethene and cis-Dichloroethene by PCB-Dechlorinating Bacterium DF-1.  Environ. Sci. Technol., 39:2631-2635 [ABSTRACT].

Watts, J.E.M., S.K. Fagervold, G.S. Miller, C.E. Milliken, H.D. May and K.R. Sowers.  2004.  Microbial Reductive Dechlorination of Organochlorine Pollutants in the Marine Environment.  J. Mar. Biotechnol., 6 (Supplement 1): S378-S386.

Nicholas J. Drenzek, Christopher M. Reddy, Timothy I. Eglinton, Carl O. Wirsen, Harold D.  May, Neil C. Sturchio, Linnea J. Heraty, Kevin R. Sowers, and Qingzhong Wu.  2004.  Invariant Chlorine Isotopic Signatures During PCB Reductive Dechlorination.  Environmental Pollution 128: 445-448. 

Sowers, K.R., J. E. M. Watts, S. K. Fagervold and H. D. May.  2003.  Environmental Distribution and Diversity of the 16S rDNA Sequences of Microorganisms that Reductively Dechlorinate Polychlorinated Biphenyls (PCBs) in Coastal Sediments.  Abstr. 6th International Marine Biotechnology Conference, Tokyo, Japan.

Miller, G., C.E. Milliken, K.R. Sowers and H.D. May.  2003.  Dechlorination of chlorinated ethenes and benzenes by PCB-dechlorinating bacteria.  Abstr. 103rd Ann. Mtg. Amer. Soc. Microbiol., Washington, DC.    

Fagervold, S.K., J. E.M. Watts, H.D. May and K.R. Sowers.  2003.  Identification of microorganisms associated with the reductive dechlorination of specific PCB congeners.  Abstr. 103rd Ann. Mtg. Amer. Soc. Microbiol., Washington, DC.  

May, H.D., C.E. Milliken, G. Miller, Q. Wu, L.A. Cutter, G.P. Meier,  J.E.M. Watts, and K.R. Sowers.  2002.  PCB-Dechlorinating Bacteria and the Halogen Cycle.  Southeastern Branch of the Amercian Society of Microbiology Annual Meeting, Gainsville, Florida.  November 7-9.  

Watts, J.E.M., May, H.D., and Sowers, K.R.  2002.  Development of a molecular screening  technique for microorganisms that reductively dechlorinate PCBs in the environment.  Abstr. Society of Industrial Microbiology., Philadelphia, PA.

Drenzek, Nicholas J., Christopher M. Reddy, Timothy I. Eglinton, Carl O. Wirsen, Harold D.  May, Neil C. Sturchio, Linnea J. Heraty, Kevin R. Sowers and Qingzhong Wu, and.  2002.  Static chlorine isotopic signatures during PCB reductive dechlorination. 224th American Chemical Society Meeting.  Boston, MA  August 18-22.

Wu, Q., G.P. Meier, K.R. Sowers, and H.D. May.  2002.  Reductive dechlorination of polychlorinated benzenes by Bacterium DF-1, a polychlorinated biphenyl-dechlorinating microorganism.  Environ. Sci. & Technol. 36(15):3290-4.

Wu, Q., Watts, J.E.M., K.R. Sowers and H.D. May.  2002.  Identification of a bacterium that Catalyzes double-flanked PCB dechlorination.  Appl. Environ. Microbiol. 69(2): 807-812.

Cutter, L.A., J.E.M. Watts, R.R. Hebert, K.R. Sowers and H.D. May.  2001.  Identification of a  Bacterium that links its growth to the reductively dechlorination of 2,3,5,6-chlorobiphenyl. Environ. Microbiol. 3(11): 699-709.

Watts, J.E.M., S. B. Schreier, L. A. Cutter, Q. Wu, H. D. May and K. R. Sowers.  2001.    Molecular Analysis and Identification of a Phylogenetically Distinct PCB Dechlorinating Group  from Three Anaerobic PCB Degrading Communities.  Ninth International Symposium on Microbial Ecology, Amsterdam.

Watts, J.E.M., Q. Wu, S.B. Schreier, H.D. May and K.R. Sowers.  2001.  Comparative analyses of PCB dechlorinating communities in enrichment cultures using three different molecular screening techniques.  Environ. Microbiol. 3(11): 710-719.

Drenzek, N.J., T.I. Eglinton, C.O. Wirsen, H.D. May, Q. Wu, K.R. Sowers, and C.M. Reddy.  2001.  The absence and application of stable carbon isotope fractionation during the reductive dehalogenation of polychlorinated biphenyls.  Environ. Sci. Technology. 35: 3310-3313.

Wu, Q., K.R. Sowers and H.D. May.  2000.  Establishment of a PCB-dechlorinating microbial consortium, specific for doubly-flanked chlorines, in a sediment-free medium.  Appl. Environ.  Microbiol. 66: 49-53.

Watts, J.E.M., S. B. Schreier, Q. Wu, H. D. May and K. R. Sowers. 2000. An examination of  microbial diversity in polychlorinated biphenyl (PCB) polluted Baltimore Harbour sediment.  Int. Mar. Biotechnol. Conf., Townsville, Australia.

Holoman, T.R.P., M.A. Elberson, L. Cutter, H.D. May and K.R. Sowers.  1998.  Characterization of a defined 2,3,5,6-tetrachlorobiphenyl ortho-dechlorinating microbial community by comparative sequence analysis of genes coding for 16S rDNA.  Appl. Environ. Microbiol. 64: 3359-3367.  

Cutter, L., K.R. Sowers and H.D. May.  1998.  Ortho-declorination of 2,3,5,6,-chlorinated biphenyl by estuarine microbial populations in sediment-free enrichment cultures. Appl. Environ. Microbiol. 64: 2966-2969.

Wu, Q., K.R. Sowers and H.D. May.  1998.  Microbial reductive dechlorination of Aroclor 1260 in anaerobic slurries of estuarine sediments. Appl. Environ. Microbiol. 64: 1052-1058.

Berkaw, M., K.R. Sowers, and H.D. May.  1996.  Anaerobic ortho-dechlorination of polychlorinated biphenyls by estuarine sediments from Baltimore Harbor.  Appl. Environ. Microbiol. 62: 2534-2539.

 

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