Biodegradation of methyl tert-butyl ether by a pure bacterial culture

Biodegradation of methyl tert-butyl ether (MTBE) by the hydrogen-oxidizing bacterium Hydrogenophaga flava ENY735 was evaluated. ENV735 grew slowly on MTBE or tert-butyl alcohol (TBA) as sole sources of carbon and energy, but growth on these substrates was greatly enhanced by the addition of a small amount of yeast extract. The addition of H, did not enhance or diminish MTB E degradation by the strain, and MTBE was only poorly degraded or not degra ded by type strains of Hydrogenophaga or hydrogen-oxidizing enrichment cult ures, respectively. MTBE degradation activity was constitutively expressed in ENV735 and was not greatly affected by formaldehyde, carbon monoxide, al lyl thiourea, or acetylene. MTBE degradation was inhibited by 1-amino benzo triazole and butadiene monoepoxide. TBA degradation was inducible by TBA an d was inhibited by formaldehyde at concentrations of >0.24 mM and by acetyl ene but not by the other inhibitors tested. These results demonstrate that separate, independently regulated genes encode MTBE and TBA metabolism in E NV735.