• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2004.04a
• /
• pp.147-152
• /
• 2004

Aerobic cometabolism of cis-1,2-dichloroethylene (c-DCE) and c-DCE epoxide by a butane-grown mixed culture was evaluated. Transformation of c-DCE resulted in the concomitant generation of c-DCE epoxide. Chloride release studies showed nearly complete oxidative dechlorination of c-DCE (approximately 75%). Mass spectrometry confirmed tile presence of a compound with mass-to-charge-fragment ratios of 112, 83, 48, and 35. The values are in agreement with the spectra of a chemically synthesized c-DCE epoxide. Some evidences indicating the involvement of the monooxygenase in the transformation of c-DCE epoxide are: 1) $O_2$ requirement for c-DCE transformation and butane degradation; 2) butane inhibition on c-DCE transformation and vice versa; 3) the inactivation of c-DCE and c-DCE epoxide transformations by acetylene (a known monooxygenase inactivator); and 4) tire inhibition of c-DCE epoxide transformation by c-DCE.

• Journal of Soil and Groundwater Environment
• /
• v.8 no.1
• /
• pp.27-34
• /
• 2003

In this study, potential degradation of MTBE and other gasoline oxygenates by pure culture ENV425 and mixed culture isolated from gasoline contaminated soil using butane as the sources of carbon and energy was examined and compared. Butane monooxygenases(BMO) of butane-grown ENV425 and mixed culture generated 1-butanol as a major metabolite of butane oxidation and addition of acetylene, specific inhibitor of monooxygenase, inhibited both butane oxidation and 1-butanol production. The results described in this study suggest that alkanes including propane, pentane, and butane are effectively utilized as a growth substrate to oxidize MTBE cometabolically. And also BTEX compounds could be the potential substrate of the MTBE cometabolism. Cell density also affected on the MTBE degradation and transformation capacity(Tc). Increasing cell density caused increasing MTBE degradation but decreased transformation capacity. Other result demonstrated that MTBE and other gasoline oxygenates, ETBE and TAME, were degraded by butane-grown microorganism.

• Journal of Soil and Groundwater Environment
• /
• v.6 no.3
• /
• pp.31-41
• /
• 2001

In this study, we have examined the potential degradation of MTBE(methyl tert-butyl ether) by pure culture ENV425 and mixed culture obtained from gasoline contaminated soil using n-butane as the sources of carbon and energy. The results described in this study suggest that MTBE is degraded cometabolically by ENV425 and mixed culture grown on n-butane. Butane and MTBE degradation was completely inhibited by acetylene, which indicated that both substrates were degraded by butane monooxygenase. These cultures grown on n-butane generated TBA (tert-butyl alcohol) as a metabolite of MTBE oxidation. TBA Production was accounted 54.7% and 58.6% for MTBE oxidation by ENV425 and mixed culture, respectively. In resting cell experiments, however, TBA and TBF were detected as the oxidation products of MTBE by ENV425 and mixed culture. The observed maximal MTBE degradation rates were 52.3 and 62.3 (nmol MTBE degraded/hr/mg TSS) by ENV425 and mixed culture, respectively, and the observed maximal transformation yields ($T_y$) were 44.7 and 34.0 (nmol MTBE degraded/$\mu$mol n-butane utilized), and the observed maximal transformation capacities ($T_c$) were 199 and 226 ($\mu$mol MTBE degraded/mg TSS used).