Abstract
The dechlorinating activity of a methanogenic granular sludge from a methanol-fed upflow anaerobic sludge blanket reactor was investigated with chlorinated ethanes. This unadapted methanogenic consortium degraded all chloroethanes tested. The product formation rates decreased with the number of chlorine substituents. The more highly chlorinated ethanes were also converted, although at a lower rate, in the presence of autoclaved (dead) sludge, indicating the involvement of reduced heat-stable cofactors like vitamin B12 and F430. Direct chemical dechlorination of hexa-, penta- and tetrachloroethanes was also observed in medium without sludge, although at a much lower rate. The results show the importance of cometabolic and abiotic (chemical) conversions for the transformation of chlorinated ethanes by the methanogenic consortium. The types of reaction and the products formed were correlated with the Gibbs free-energy change (ΔG 0′). Reductive hydrogenolysis and dichloroelimination were important dechlorinating mechanisms. Generally, these reactions have a higher ΔG 0′ value than dehydrochlorination reactions, which occurred less frequently during the transformation of chloroethanes by the methanogenic granular sludge.
Similar content being viewed by others
Author information
Authors and Affiliations
Additional information
Received: 8 June 1998 / Received revision: 7 September 1998 / Accepted: 13 September 1998
Rights and permissions
About this article
Cite this article
van Eekert, M., Stams, A., Field, J. et al. Gratuitous dechlorination of chloroethanes by methanogenic granular sludge. Appl Microbiol Biotechnol 51, 46–52 (1999). https://doi.org/10.1007/s002530051361
Issue Date:
DOI: https://doi.org/10.1007/s002530051361