Microbial structure of an anaerobic bioreactor population that continuously dechlorinates 1,2-dichloropropane

The bacterial diversity of an anaerobic 1,2-dichloropropane (DCP) dechlorinating bioreactor consortium derived from river sediment has been investigated by a combined molecular approach. By using rDNA clone libraries, denaturing gradient gel electrophoresis and quantitative real-time PCR, both Dehalococcoides ethenogenes- and Dehalobacter restrictus-like 16S rDNA sequences were found within the community. Both species are known for reductive dechlorination of tetrachloroethene. Furthermore, numerous yet-uncultured members of the Green non-sulfur bacteria occurred within the consortium. The community analyses over a period of 14 months revealed a clear population shift. D. restrictus 16S rDNA was enriched significantly and became the most abundant rDNA sequence type, suggesting that Dehalobacter spp. play a key role within the reductive dechlorination of DCP in this consortium. We propose the use of this species as an indicator to monitor the transformation process within the bioreactor. (C) 2002 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.