Activity: Talks and presentations › Guest lectures, external teaching and course activities at other universities
Necessity builds friendships in dark anoxic environments. For more than four decades hydrogen was thought to be the prime messenger of microbial interspecies interactions. For example, a Pelobacter strain cannot grow on ethanol alone in the absence of an electron acceptor, however if provided with a hydrogen-scavenging methanogen, the otherwise unfavorable ethanol oxidation in Pelobacter becomes favorable. During my stay at UMass, I studied another mechanism by which microorganisms interacted by transferring electrons using conductive extracellular structures – pili – rather than chemical messengers. During my talk I will discuss studies on defined co-cultures of methanogens with Geobacter, and their implication in methanogenic decomposition of waste in brewery digesters. Physiological experiments, mutant studies, and incubations with 14C-radiolabeled substrates indicated microbes were wired for life - interacting by exchanging electrons - rather than hydrogen.
There are plenty of questions left unanswered regarding the distribution of DIET- based associations with methanogens in the environment, how methanogens receive electrons directly, what is the ecological advantage of DIET over HIT, and what is the possible impact of climate change on DIET based associations. I am now investigating some of these questions at the University of Southern Denmark.
Invited Seminar Series, Center for Geomicrobiology, Aarhus University