Trace-gas metabolic versatility of the facultative methanotroph Methylocella silvestris

• Published in: Nature (London) 2014-06, Vol.510 (7503), p.148-151
• Main Authors: Crombie, Andrew T., Murrell, J. Colin
• Format: Article
• Language: English
• Subjects: 631/326/47; 631/45/607/1168; 704/106/694; 704/158/855; Anthropogenic factors; Bacterial proteins; Beijerinckiaceae - enzymology; Beijerinckiaceae - genetics; Beijerinckiaceae - growth & development; Beijerinckiaceae - metabolism; Carbon; Carbon - metabolism; Energy sources; Enzyme Induction - drug effects; Enzymes; Ethane; Gases; Gases - metabolism; Gases - pharmacology; Gene Expression Regulation, Bacterial - drug effects; Genes; Genetic engineering; Global Warming; Humanities and Social Sciences; letter; Metabolism; Metabolites; Methane; Methane - metabolism; Methane - pharmacology; Methanotrophs; Microbiological research; Microorganisms; Mixed Function Oxygenases - genetics; Mixed Function Oxygenases - metabolism; multidisciplinary; Multigene Family - genetics; Natural gas; Physiological aspects; Propane; Propane - metabolism; Propane - pharmacology; Proteins; Science
• ISSN: 0028-0836; 1476-4687
• DOI: 10.1038/nature13192

Distinct groups of microorganisms have been thought to grow on methane and on short-chain alkanes; now, the methanotroph Methylocella silvestris is shown to express two distinct soluble di-iron centre monooxygenases that allow it to use either methane or propane as a carbon and energy source. Methanotroph adds protein to menu Methane is a potent greenhouse gas, and increasing anthropogenic emissions of methane to the atmosphere could have a major impact on climate. Microorganisms can use methane and short-chain alkanes such as propane and butane as an energy source, and it had been assumed that these gases were oxidized by completely different groups of organisms. Now Andrew Crombie and John Murrell show that the facultative methanotroph Methylocella silvestris BL2 encodes two distinct soluble di-iron centre monooxygenase gene clusters, equipping it to use either methane or propane as a carbon and energy source. The ability of an environmentally widespread strain to degrade both methane and propane underlines the importance of microbial processes in climate modelling as well as in oil spills, unconventional methods of gas extraction and other human activities. The climate-active gas methane is generated both by biological processes and by thermogenic decomposition of fossil organic material, which forms methane and short-chain alkanes, principally ethane, propane and butane 1 , 2 . In addition to natural sources, environments are exposed to anthropogenic inputs of all these gases from oil and gas extraction and distribution. The gases provide carbon and/or energy for a diverse range of microorganisms that can metabolize them in both anoxic 3 and oxic zones. Aerobic methanotrophs, which can assimilate methane, have been considered to be entirely distinct from utilizers of short-chain alkanes, and studies of environments exposed to mixtures of methane and multi-carbon alkanes have assumed that disparate groups of microorganisms are responsible for the metabolism of these gases. Here we describe the mechanism by which a single bacterial strain, Methylocella silvestris , can use methane or propane as a carbon and energy source, documenting a methanotroph that can utilize a short-chain alkane as an alternative to methane. Furthermore, during growth on a mixture of these gases, efficient consumption of both gases occurred at the same time. Two soluble di-iron centre monooxygenase (SDIMO) gene clusters were identified and were found to be differentially expressed