Microbial degradation of pollutants at high salt concentrations

The treatment of chemically contaminated high-salinity lakes, using microorganisms is discussed. The presently available information on the biodegradation of pollutants at high salt concentrations, under both aerobic and anaerobic conditions, and the bacteria involved in these processes are reviewed. Results are presented from laboratory experiments designed to investigate the biodegradation of formaldehyde at high salt concentrations by halotolerant eubacteria, and the transformation of nitroaromatic compounds by anaerobic halophilic eubacteria. In the formaldehyde experiments, a rod-shaped Gram-negative, motile eubacterium called MA-C was found to grow well at sodium chloride concentrations in the range 0 20%, and possibly higher. In the nitroaromatics evaluations, Haloanaerobium praevalens and Sporohalobacter marismortui, isolated from the Great Salt Lake and the Dead Sea, respectively, were shown to reduce p-nitrophenol to p-aminophenol in the presence of 13 14% NaCl.