Technology Spotlight | Gene-Trac® MTBE/TBA

Technology Spotlight | Gene-Trac® MTBE/TBA

Methyl tert-butyl ether (MTBE) was widely used as a gasoline additive, replacing lead as an antiknocking agent. Tert-butyl alcohol (TBA), a breakdown product of MTBE, and a gasoline additive in its own right, is also used as a solvent. MTBE and TBA are toxic and potentially carcinogenic compounds, that are also extremely mobile in groundwater, often creating large groundwater plumes. For these reasons, both compounds are regulated contaminants in several US States. Fortunately, biodegradation of MTBE/TBA is commonly reported via aerobic pathways; although these compounds are often more recalcitrant than the fuel which introduced them to groundwater.

As part of a growing suite of Gene-Trac® tests, SiREM now offers targets for the biodegradation of MTBE and TBA that focus on a key MTBE degrading microorganism and functional genes. Methylibium petroleiphilum PM1 was isolated from a culture enriched with MTBE from a biofilter. M. petroleiphilum PM1 is widely found in MTBE contaminated groundwater and is considered a major organism involved in degradation of MTBE and TBA1,2.

M. petroleiphilum PM1 is a key aerobic biodegrader of MTBE and TBA. From: Joint Genome Institute

Key functional genes active in the degradation of MTBE/TBA include tert-butyl alcohol hydroxylase (mdpJ) which is active on TBA2 and the HIBA mutase (hcmA) active further down the pathway converting 2-hydroxyisobutyric acid (2-HIBA) to 3-hydroxybutyric acid4 which is ultimately degraded to CO2.

Gene-Trac® MTBE/TBA is a three-test suite that includes quantification of the M. petroleiphilum PM1 16S rRNA gene, the TBA hydroxylase (mdpJ) and the HIBA mutase (hcmA) genes. The combination of these three tests provides breadth in the detection of MTBE and TBA degradation activity with positive test results implying a high likelihood of biodegradation capacity for these contaminants.

For more information on Gene-Trac® MTBE/TBA or molecular tests for other compound classes contact Phil Dennis
( toll free 1-866-251-1747/direct 519-515-0836.