The Analysis of Methyl Tertiary Butyl Ether Biodegradation by a Novel Azotobacter Vinelandii Strain Isolated from Contaminated Soils of Imam Khomeini Port Petrochemical Company (Iran)

Methyl Tertiary Butyl Ether (MTBE (is a highly soluble and low degradable oxygenated supplement to fuel that causes rapid contamination of soil and water. The present study aimed to isolate and identify the potent MTBE degrading bacteria from the petrochemical soil of Imam Khomeini Port (Iran), as well as the finding of the best temperature and pH for MTBE degradation.

Samples were taken from contaminated soils of Mahsahar MTBE production site in Imam Khomeini Petrochemical Company. Enrichment and isolation of MTBE degrading bacteria were done in Basal Salt Medium (BSM) containing 50 mg/l MTBE followed by increasing the MTBE concentration up to 400 mg/l during 5 enrichment steps. The MTBE degradation process by the isolated bacterium was assessed by the GC method. The MTBE degrading isolate was identified by the amplification and sequencing of 16S rRNA gene. Finally, the MTBE degradation potential of the bacterium was detected in different temperatures (25-37 ºC) and pH values (6.5-7.5).

The MTBE degrading bacterium was identified as Azotobacter vinelandii. The results of MTBE degradation showed that the bacterium is a potent MTBE degrading strain with the degradation ability of 91.29% during 21 days. The highest MTBE degradation by the bacterium was obtained at 30 ⁰C and pH=7 with no significant differences.

Azotobacter vinelandii strain isolated in the present study had the high ability to degrade high amounts of MTBE during 14 days of incubation without the need for the addition of co-catalytic substrate and is proposed for the removal of this pollutant from contaminated soil ecosystems.