IngentaConnect Cyanocobalamin Enables Activated Sludge Bacteria to Dechlorinate ...

Authors: James, D. L.¹; Cord-Ruwisch, R.¹; Schleheck, D.²; Lee, M. J.²; Manefield, M.²

Source: Bioremediation Journal, Volume 12, Number 4, October 2008 , pp. 177-184(8)

Abstract:

The ability of activated sludge obtained from a local wastewater treatment plant to dechlorinate hexachloro-1,3-butadiene (HCBD) in the presence of either acetate or lactate and cyanocobalamin was investigated. Results from headspace analysis indicated complete dechlorination of HCBD by the accumulation of fully dechlorinated C4 gases (1-buten-3-yne, 1,3-butadiene, and 1,3-butadiyne). Dechlorination products were not observed in the control cultures without cyanocobalamin. Examination of control cultures revealed that the disappearance of HCBD from the headspace was partly due to adsorption into the biomass. However, the key for dechlorination was the shuttle (cyanocobalamin) rather than specific microbial enzymatic activity. The hypothesis that the bacteria reduced cyanocobalamin, which in turn reductively dechlorinated HCBD, was supported by the finding that cyanocobalamin reduced by zero-valent zinc resulted in complete dechlorination. The significance of the findings is that, in contrast to prior work where specific anaerobic bacteria (enrichments or pure cultures) were believed to be necessary for dechlorination resulting in only partly dechlorinated products, the currect data show that nonspecific aerobic activated sludge bacteria can be employed for complete HCBD dechlorination at rates sufficiently high to be considered for bioremediation projects.

Keywords: 1-buten-3-yne; 1,3-butadiene; 1,3-butadiyne; activated sludge; cyanocobalamin; hexachloro-1,3-butadiene (HCBD); reductive dechlorination

Document Type: Research article

DOI: 10.1080/10889860802477085

Affiliations: 1: Department of Science and Engineering, School of Biological Sciences and Biotechnology, Murdoch University, Murdoch, Western Australia, Australia 2: Centre for Marine Biofouling and BioInnovation, School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, Australia

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Cyanocobalamin Enables Activated Sludge Bacteria to Dechlorinate Hexachloro-1,3-butadiene to Nonchlorinated Gases