The Effect of BTX Compounds on the Biodegradation of ETBE by an ETBE Degrading Bacterial Consortium

摘要

Ethyl tert-butyl ether (ETBE) is a fuel oxygenate that is commonly used in Europe to achieve complete combustion of automobile fuels and to control air pollution. It is potentially toxic and can enter the human system via contaminated water bodies. In the present study, we have identified an enriched bacterial consortium from a gasoline-contaminated site that can degrade ETBE. Bacterial consortium A was able to degrade 47% of the added ETBE in 4 days and it continued to degrade up to 51% in 9 days. Consortium A consisted of Xanthomonas sp., Methylibium sp., Methylobacillus sp., and Methylovorus sp. which were identified as the participating bacteria during ETBE degradation by DGGE - 16S rDNA analysis. In addition to ETBE, this consortium degraded benzene, toluene and xylene isomers (BTX) when they were present as the sole carbon source. The degradation efficiency increased predominantly when ETBE was included as an additional carbon source. Interestingly, the degradation of ETBE decreased to 14% in 9 days when present with BTX compounds. We report that ETBE degradation is slowed down or inhibited when BTX compounds are present. This is a crucial observation for ETBE degradation in the natural environment.