Molecular characterization of sulfate-reducing bacteria in anaerobic hydrocarbon-degrading consortia and pure cultures using the dissimilatory sulfite reductase (dsr AB) genes

The characterization of sulfate-reducing bacteria (SRBs) is presented using the dissimilatory sulfite reductase (dsrAB) gene from various samples capa ble of mineralizing petroleum components. These samples include several nov el. sulfidogenic pure cultures which degrade alkanes, toluene, and tribromo phenol. Additionally, we have sulfidogenic consortia which re-mineralize be nzene, naphthalene, 2-methylnaphthalene, and phenanthrene as a sole carbon source. In this study, 22 new dsrAB genes were cloned and sequenced. Tile d srAB genes fi om our pollutant-degrading cultures or consortia were distrib uted among known SRBs and previously described dsrAB environmental clones, suggesting that many biodegradative SRBs are phylogenetically distinct and geographically wide spread. Specifically the same dsrAB gene was discovered in independently established consortia capable of benzene, phenanthrene. a nd methylnaphihalene degradation, indicating that this particular SRB may b e a key player in anaerobic degradation of hydrocarbons in the environment. (C) 2001 Federation of European Microbiological Societies. Published by El sevier Science B.V. All rights reserved.