J.C.Murrell@uea.ac.uk

+44 (0)1603 592959 (office) / +44 (0)1603 592239 (lab)

Isoprene Degradation in the Environment

Exploring the bacterial metabolism of an abundant climate-controlling gas

Isoprene (2-methyl-1,3-butadiene) is a volatile, climate-active gas, produced by all manner of living organisms, including human beings – it is the most abundant volatile organic carbon compound in our bodies! Isoprene is thought to be involved in climate control and in the biogeochemical cycling of carbon – from which our interests stem. We are particularly interested in the pathways and genes involved in isoprene degradation in a variety of model organisms with the hope to develop functional markers for future ecological studies.

Isoprene is produced by a variety of living organisms, such as plants, fungi, bacteria and animals – including humans. The exact role of isoprene is not known in most species, though it appears to be involved in the protective mechanisms from heat-shock in plants – more isoprene is produced when plants are incubated in hotter environments. Isoprene is chemically very reactive and volatile. In the upper atmosphere, isoprene can react with oxygen in the presence of oxides of nitrogen to produce ozone (O3), which has obvious environmental consequences. Our interest in isoprene at UEA concerns its metabolism by bacteria. This has been studied to some level by a number of groups over the years though the story is far from complete. A soluble-diiron centred monooxygenase, isoprene monooxygenase, IsoA, has been proposed:

In this figure (after van Hylckama Vlieg et al. 2000), the genes encoding the various subunits of isoprene monooxygenase are shown in their cluster, along with the putative pathway of metabolism in Rhodococcus sp. Strain AD45. We are currently isolating and characterising new isoprene-degrading bacteria and developing cultivation-independent methods to determine their distribution and activity in cycling of isoprene in the terrestrial and marine environment.

References

van Hylckama Vlieg J et al. (2000) Characterization of the gene cluster involved in isoprene metabolsim in Rhodococcus sp. Strain AD45. J. Bacteriol. 182: 1956-1963.

For more information on Isoprene Research click here.