Biodegradation of BTEX at high salinity by an enrichment culture from hypersaline sediments of Rozel Point at Great Salt Lake

Aims: The primary goal of this research was to assess the biodegradation of benzene, toluene, ethylbenzene and xylenes in sediment from Great Salt Lake, near Rozel Point, UT. Methods and Results: An enrichment culture that degraded benzene or toluene as the sole carbon source at high salinity was developed from a sediment sample obtained from Rozel Point. The enrichment degraded benzene or toluene within 1, 2 and 5 weeks in the presence of 14%, 23% and 29% NaCl respectively. PCR studies using degenerate primers revealed that degradation occurred primarily via catechol and the meta-cleavage pathway. Molecular analysis showed that the Gammaproteobacteria were the dominant members of the enrichment and that shifts in community composition occurred during benzene metabolism. Conclusions: This study demonstrated that micro-organisms at Rozel Point have the ability to degrade hydrocarbons over a broad range of salinities (1-5 mol l-1 NaCl) and that the members of the Gammaproteobacteria class play an important role in the degradation process. Significance and Impact of the Study: These results are significant as little is known about the fate of petroleum seeps at Rozel Point. Also, the identity of microbes and the key enzymes involved in the degradation steps are important for understanding natural attenuation potential of hydrocarbons.