Methyl tertiary butyl ether biodegradation by the bacterial consortium isolated from petrochemical wastewater and contaminated soils of Imam Khomeini Port Petrochemical Company (Iran)

Abstract

Methyl tertiary butyl ether (MTBE) is a high soluble oxygenated supplement to fuel that may rapidly contaminate water and soil. Low biodegradability of this compound in the environment has led to more extensive efforts for finding powerful MTBE degrading microbial populations to be used in biological treatment of polluted waters and soils. The present study aimed to isolate MTBE degrading bacteria from petrochemical wastewater and soil of Mahsahar MTBE production site (Iran), and increasing their biodegradation potential in a bacterial consortium. Enrichment of degrading bacteria was done in basal salt media (BSM) containing 50–400 mg/l MTBE. The MTBE degradation pattern was assessed via gas chromatography (GC). The isolates were identified molecularly based on the sequence of 16S rRNA gene. The growth and degradation potential of bacterial consortium was optimized in different pH and temperatures. The best MTBE degrading bacteria were identified as Pseudomonas putida, Pseudomonas aeruginosa, and Enterobacter oryzendophyticus. The first order kinetics for MTBE degradation showed that the bacterial consortium was able to degrade 99.93% of MTBE during 15 days that was 6.08% higher than the most putative monoculture bacterium. The highest MTBE degradation by bacterial consortium was obtained at 30 °C and pH value of 7. The isolated bacterial consortium that involved novel MTBE degrading bacterial strains, decomposed high amounts of MTBE during 15 days of incubation in different temperatures and pH values without addition of co-catalytic substrate is proposed for cost effective removal of this pollutant from the environment.