Biodegradation of methyl tert-butyl ether by newly identified soil microorganisms in a simple mineral solution
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Methyl tert-butyl ether (MTBE) is a widely used fuel ether, which has become a soil and water contaminant. In this study, 12 microbial strains were isolated from gasoline-contaminated soils and selected because of their capacity to grow in MTBE. The strains were identified by 16S/ITS rDNA gene sequencing and screened for their ability to consume MTBE aerobically in a simple mineral solution. Solid phase microoextraction and gas chromatography were used to detect MTBE degradation. High levels of MTBE biodegradation were obtained using resting cells of the bacteria Achromobacter xylosoxidans MCM1/1 (78%), Enterobacter cloacae MCM2/1 (50%), and Ochrobactrum anthropi MCM5/1 (52%) and the fungus Exophiala dermatitidis MCM3/4 (14%). Our phylogenetic analysis clearly shows that bacterial MTBE biodegraders belong to the clade of Proteobacteria. For further insight, MTBE-degrader strains were profiled by denaturing gel gradient electrophoresis (DGGE) of PCR-amplified 16S rRNA gene sequences. This approach could be used to analyse microbial community dynamics in bioremediation processes.
KeywordsMTBE biodegradation Resting cells Achromobacter xylosoxidans Enterobacter cloacae Ochrobactrum anthropi Exophiala dermatitidis
This study was supported by a project grant from the Spanish Ministerio de Medio Ambiente. We are grateful to Nuria Forns and Josep Matías for their help in selecting and identifying the microorganisms, to Iñaki Ruiz-Trillo for the phylogenetic analysis, Josep M. Borràs for his chromatographic assistance and Josep M. Mateo for his statistical suggestions. Rasa Monkaityte was a recipient of a PhD grant from the Generalitat de Catalunya, Spain
Conflict of interest
The authors declare that they have no conflict of interest.
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