Linking Low-Level Stable Isotope Fractionation to Expression of the Cytochrome P450 Monooxygenase-Encoding ethB Gene for Elucidation of Methyl tert -Butyl Ether Biodegradation in Aerated Treatment Pond Systems

• DOI: 10.1128/aem.01698-10
• Publication Date: 2010-12-11T04:14:54Z
• Authors: Sven Jechalke; Mònica Rosell; Paula M. Martíne...; Paola Pérez-Leiva; Thore Rohwerder; Carsten Vogt; Hans H. Richnow
• Keywords: Microcosm; Methyl tert-butyl ether

Multidimensional compound-specific stable isotope analysis (CSIA) was applied in combination with RNA-based molecular tools to characterize methyl tertiary (tert-) butyl ether (MTBE) degradation mechanisms occurring biofilms an aerated treatment pond used for remediation of MTBE-contaminated groundwater. The main pathway MTBE oxidation elucidated by linking the low-level fractionation (mean carbon isotopic enrichment factor [ε(C)] -0.37‰ ± 0.05‰ and no significant hydrogen [ε(H)]) observed microcosm experiments expression ethB gene encoding a cytochrome P450 monooxygenase able catalyze biofilm samples both from microcosms directly ponds. 16S rRNA-specific primers revealed presence sequence 100% identical that Methylibium petroleiphilum PM1, well-characterized degrader. However, neither mdpA genes alkane hydroxylase-like enzyme responsible this strain nor related pattern produced PM1 could be detected, suggesting not active system. Additionally, low inverse (ε(C) +0.11‰ 0.03‰) (ε(H) -5‰ 1‰) laboratory simulating stripping open surface water body suggest application CSIA field investigations detect biodegradation may lead false-negative results when volatilization effects coincide activity low-fractionating enzymes. As shown study, complementary examination specific catabolic can as additional direct evidence microbial overcome problem.