The reason that Methylomonas is found in methane rich environments is because methane is utilized as the primary source of carbon and energy. The oxidation of methane occurs by the use of mehtane-oxygenase and generates reducing power for energy production by the oxidizing of methane to carbon dioxide. Methane is oxidized to methanol, which is then converted to formaldehyde. The formaldehyde is then further converted to formic acid which is broken down into the final by-products carbon dioxide and water.
Methylomonas is a Type I bacterium containing a complex internal arrangement of paired membranes comprising bundles of vesicular discs (see image to left). Methane, methanol, methyl formate, dimethylcarbonate and formaldehyde are its sole carbon and energy sources. It is capable of redusing nitrate to nitrite and uses ammonia as its nitrogen source. They are gram negative rods and are obligate aerobes. Motility is made possible by a polar flagella which single or arranged in tufts. Carbon is assimilated via the RuMP pathway and has an incomplete TCA cycle. Predominant fatty acid is a saturated fatty acid with 16 carbon atoms. As the culture enters the stationary phase Azotobacter-type cysts are formed, which are resistant to desiccation. Genus from the family METHYLOCOCCACEAE.
Methylomonas can be isolated and enriched by first using liquid and then a mineral salt agar-solidified medium and a nitrogen source (e.g. nitrate) under an atmosphere of 1 part methane and 1 part air. After an incubation period of 6-10 days at 30?C, a pink film or pellicle may form. This pink film or pellicle can be streaked on agar plates of the same medium.
Widely distributed in soils, mud, and water. It is also found naturally in surface layers of wetland soils, unsaturated upland soils, and in flooded environments. Methylomonas strives in areas where methane is produced and made available for oxidation, such as well-drained soils, paddy fields, pond mud, barnyard manure, and sewage.
Anthony, C. 1982. The Biochemistry of Methylotrophs. Academic Press, Inc. New York. p.4-19.
Cook, T.M. and R.N. Doetsch. 1973. Introduction to Bacteria and Their Ecobiology. University Park Press. Baltimore, Maryland. p.119.
Dow, Crawford S. and Robert K. Poole. 1985. Microbia Gas Metabolism. Academic Press, Inc. Orlando,Florida. p.173-175.
Gerba, Charles P., Raina M. Maier, and Ian L. Pepper. 2000. Environmental Microbiology. Academic Press. San Diego, California. p.330.
Sainsbury, Diana and Paul Singleton. 1987. Dictionary of Microbiology and Molecular Biology. Second Edition. John Wiley & Sons Ltd. New York, New York. p.540-541.
Stolp, Heinz. 1988. Microbial Ecology: Organisms, Habitats, and Activities. Cambridge University Press. New York, NY. p.231.
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