Methyl tert-butyl ether (MTBE) degradation by a microbial consortium

Area of Science:

• Environmental Microbiology
• Bioremediation
• Environmental Chemistry

Background:

• Methyl tert-butyl ether (MTBE) is a widespread gasoline additive causing significant groundwater contamination.
• Bioremediation is a promising treatment, but MTBE biodegradation differs from typical gasoline contaminants like BTEX.
• Understanding MTBE-degrading microbial consortia is crucial for effective remediation.

Purpose of the Study:

• To characterize a microbial consortium capable of degrading MTBE in liquid cultures.
• To evaluate the degradation kinetics, efficiency, and substrate range of the consortium.
• To identify factors influencing MTBE biodegradation for potential in situ applications.

Main Methods:

• Culturing and characterization of MTBE-degrading microbial consortia.
• Batch degradation experiments to determine kinetics and efficiency.
• Radioisotope tracer studies to track carbon conversion.
• Analysis of degradation of various hydrocarbons including MTBE, TBA, TAME, and BTEX.

Main Results:

• The consortium exhibited rapid MTBE degradation (zero-order kinetics at 100 mg/L) with residual concentrations below 50 µg/L.
• Specific activity ranged from 7 to 52 mg MTBE/g(dw)/h, with 79% of carbon-MTBE converted to CO2.
• The consortium degraded MTBE, TBA, TAME, and BTEX, but showed slow growth (0.1 d⁻¹) and low biomass yield.
• High affinity for MTBE and low affinity for oxygen were observed, potentially explaining slow in situ degradation.

Conclusions:

• The characterized consortium demonstrates high efficiency in degrading MTBE and other gasoline-related hydrocarbons.
• The consortium's metabolic characteristics present promising avenues for developing engineered in situ bioremediation strategies for MTBE-contaminated sites.
• Further research into optimizing conditions for in situ application is warranted.