Stable Isotope Probing Implicates Pseudomonas as the Methanogenic Toluene Degrader in Gasoline-Contaminated Soil

摘要

Anaerobic toluene-degrading enrichment cultures inoculated from gasoline-contaminated soil were maintained for more than 3 years, using toluene as the carbon source and CO2 as electron acceptor. A large amount of methane was produced and toluene biodegradation was observed from these enrichment cultures, indicating that methanogenic toluene biodegradation may occur in these cultures. Furthermore, DNA-SIP was used to identify toluene-degrading bacteria in these methanogenic enrichment cultures. The current SIP experiments indicated that bacteria in the phylum Proteobacteria (genus Pseudomonas) may be the dominant toluene-degrading bacteria under the methanogenic conditions. In addition, bacteria related to the Simplicispira were also associated with the anaerobic toluene biodegradation, but may not be the primary toluene-degrading bacteria. The identification of novel toluene degraders expands current knowledge regarding the potential fate of toluene under methanogenic conditions.