Degradation of MTBE and TEA by a new isolate from MTBE-contaminated soil

Abstract

Methyl fcrt-butyl ether (MTBE), a gasoline additive, possesses serious problems to the environmental health. In the present study, a bacterial culture named A-3 which could effectively degrade MTBE was isolated from the MTBE contaminated soil. The isolate was identified as Chryseobacterium sp., a new species capable of degrading MTBE. In order to enhance its degradation ability, selected environment factors were investigated. The results showed that the optimal temperature was in the range of 25–30°C, the pH was 7.0, the inoculum size was 2 x 108 CFU/ml and the optimal concentration of MTBE was from 50 to 100 mg/L. The maximum MTBE utilization rate (vmax) was 102 nmol MTBE/(mg cell protein-h). Furthermore, it was found that the isolate could also degrade tert-butyl alcohol (TEA). The degradation rates of TEA were much faster than those of MTBE. The additional TEA would lead to the decrease of the initial MTBE degradation rate and the inhibitory effect of TEA increased with the increase of TEA concentration. Similar protein profiles at least seven pep tides were demonstrated after SDS-PAGE analysis of crude extracts obtained from the cells growing in MTBE and TEA culture.