Reductive dechlorination in the energy metabolism of anaerobic bacteria

Within the last few decades, several anaerobic bacteria have been isolated which are able to reductively dechlorinate chlorinated aliphatic and aromat ic compounds at catabolic rates. For some of these bacteria, it has been sh own that the reductive dechlorination is coupled to energy conservation, a process designated as 'dehalorespiration'. Somewhat simple respiratory chai ns seem to be involved that utilize the free energy that could be gained fr om the exergonic dechlorination reaction quite inefficiently. With one exce ption, all reductive dehalogenases isolated to date contain a corrinoid and iron-sulfur clusters as cofactors. During the course of the catalytic reac tion cycle, the cobalt of the corrinoid is subjected to a change in its red ox state. Hence, reductive dechlorination represents a new type of biochemi cal reaction. (C) 1999 Federation of European Microbiological Societies. Pu blished by Elsevier Science B.V. All rights reserved.