06/28/2012
Understanding How microbes Work Together: Methane Production by Partnered Microbes
Summary
Methanogenic archaea and sulfate-reducing bacteria (SRBs) both play important roles in the carbon cycle of soils, wetlands, and other environments with limited oxygen availability. SRBs are versatile consumers of a variety of organic compounds, while methanogens primarily convert hydrogen and CO2 into methane. Neither of these organisms is capable of independent growth on lactate, a small organic compound that is an important intermediate in food webs, but can consume it when working together in a partnership called syntrophy. Researchers at the University of Washington and Lawrence Berkeley National Laboratory have published a new study that helps explain how this partnership works. They carried out a high-resolution transcriptomic study of changes in gene expression of the methanogen Methaococcus maripaludis during syntrophic growth on lactate with the SRB Desulfovibrio vulgaris as a partner. The methanogen shows a substantial shift in genes associated with conversion of hydrogen to methane, switching over to a parallel set of enzymes that may be better adapted to low rates of hydrogen production and other conditions associated with syntrophy. These results advance our understanding of microbial production of a potent greenhouse gas and highlight the important role of subtle interactions between organisms that influence environmental processes.
References
Walker, C. B., A. M. Redding-Johanson, E. E. Baidoo, L. Rajeev, Z. He, E. L. Hendrickson, M. P. Joachimiak, S. Stolyar, A. P. Arkin, J. A. Leigh, J. Zhou, J. D. Keasling, A. Mukhopadhyay, and D. A. Stahl. 2012. “Functional Responses of Methanogenic Archaea to Syntrophic Growth,” The ISME Journal 6, 2045-2055. DOI: 10.1038/ismej.2012.60.