Reduction of aromatic nitro compounds in anaerobic ecosystems

The moderately halophilic anaerobic eubacteria Haloanaerobium praevalens and Sporohalobacter marismortui are able to reduce p-nitrophenol and a variety of other nitrosubstituted aromatic compounds at a high rate to the corresponding amines. p-Nitrophenol was not incorporated by the cells or degraded to acid-volatile compounds. Other compounds transformed included nitrobenzene, o-nitrophenol, m-nitrophenol, nitroanilines, 2,4-dinitrophenol, and 2,4-dinitroaniline. Also sheep rumen fluid was found to transform p-nitrophenol and a number of other nitroaromatic compounds at a high rate. At least 50% of the p-nitrophenol transformed was recovered as p-aminophenol. The findings suggest that anaerobic transformation of nitroaromatic compounds may be widespread in the bacterial world.