Andrew Crombie

2007 – 2011: NERC-funded PhD (University of Warwick)

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2011 – Present: Postdoctoral Researcher (University of East Anglia)

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Methanotrophs are bacteria able to grow using methane as sole source of carbon and energy. This compound is environmentally important since it is a potent global warming gas and has a major effect on atmospheric chemistry. My PhD focussed on the facultative methantroph Methylocella silvestris, which is unusual since it is able to use a wide range of multi-carbon compounds in addition to methane as sole source of carbon and energy. For growth on methane, M. silvestris uses a soluble form of the methane monooxygenase which is a member of the family of soluble di-iron centre monooxygenases (SDIMOs). Uniquely among methanotrophs, this organism was found to contain an additional SDIMO, with similarity to propane monooxygenases and M. silvestris was shown to have an extended growth substrate range which includes both methane and the short chain alkane propane. Currently my research is directed at bacterial degradation of another climate-active atmospheric trace gas. As a hydrocarbon emitted to the atmosphere in quantities second only to methane, the terpene isoprene is produced by plants. Some bacteria are able to use this compound as a growth substrate but their diversity and the enzymes and mechanisms employed are largely unknown. However some, at least, use an SDIMO as the first step in this metabolic pathway. Our lab is now investigating the biochemistry and regulation of isoprene degradation in environmental isolates and also in a model isoprene-degrading strain, Rhodococcus sp. AD45.