Identification of intermediates of in vivo trichloroethylene oxidation by the membrane-associated methane monooxygenase

• Published in: FEMS microbiology letters Vol. 186; no. 1; pp. 109 - 113
• Main Authors: Lontoh, Sonny, Zahn, James A., DiSpirito, Alan A., Semrau, Jeremy D.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.05.2000; Blackwell; Oxford University Press
• Subjects: Acetylene; Biodegradation, Environmental; Biological and medical sciences; Biological treatment of waters; Bioremediation; Biotechnology; Carbon dioxide; Cell Membrane - enzymology; Deactivation; Environment and pollution; Fundamental and applied biological sciences. Psychology; Inactivation; Industrial applications and implications. Economical aspects; Intermediates; Membranes; Methane; Methane monooxygenase; Methanotroph; Methylococcaceae - enzymology; Methylococcus capsulatus - enzymology; Microbiology; Oxidation; Oxidation-Reduction; Oxygen uptake; Oxygenases - metabolism; Particulate methane monooxygenase; Radioactive tracers; Solvents; Trichloroethene; Trichloroethylene; Trichloroethylene - metabolism; Trichloroethylene; Particulate methane monooxygenase; Bioremediation; Methanotroph; Metabolic intermediate; Methanotrophy; Enzyme; Metabolic pathway; Pollutant; Enzymatic activity; Chlorocarbon; Bacteria; Methane monooxygenase; Oxidation; Oxidoreductases; Ethylene(trichloro)
• ISSN: 0378-1097; 1574-6968
• DOI: 10.1111/j.1574-6968.2000.tb09090.x

Abstract The rate and products of trichloroethylene (TCE) oxidation by Methylomicrobium album BG8 expressing membrane-associated methane monooxygenase (pMMO) were determined using 14C radiotracer techniques. [14C]TCE was degraded at a rate of 1.24 nmol (min mg protein)−1 with the initial production of glyoxylate and then formate. Radiolabeled CO2 was also found after incubating M. album BG8 for 5 h with [14C]TCE. Experiments with purified pMMO from Methylococcus capsulatus Bath showed that TCE could be mineralized to CO2 by pMMO. Oxygen uptake studies verified that M. album BG8 could oxidize glyoxylate and that pMMO was responsible for the oxidation based on acetylene inactivation studies. Here we propose a pathway of TCE oxidation by pMMO-expressing cells in which TCE is first converted to TCE-epoxide. The epoxide then spontaneously undergoes HCl elimination to form glyoxylate which can be further oxidized by pMMO to formate and CO2.