Alumni lecture: Anaerobics in the microbial methane and nitrogen cycle

During the evolutionary history of our planet, a set of microbial processes that evolved exclusively in the absence of oxygen changed the chemical speciation of all major elements. In the past 20 years we aimed to discover and elucidate the role of these anaerobic microbes in the methane and nitrogen cycles. Molecular studies showed that anammox bacteria occur in many oxygen-limited ecosystems, and that they can make the rocket fuel hydrazine by novel protein complexes that are located in a unique bacterial organelle. Anaerobic oxidation of methane by Methanoperedens archaea and Methylomirabilis oxyfera bacteria have recently been discovered. M. oxyfera bacteria turned out to have a new intra-aerobic metabolism. Most if not all of these microorganisms occur in coastal sediments (Bothnian Sea, Stockholm Archipelago, lake Grevelingen) where they contribute to the removal of methane and nitrogen compounds. Several of these new an aerobes can be applied in sustainable, cost effective oxygen-limited wastewater treatment for the removal of nitrogen compounds. In this lecture, Mike Jetten will explore how microorganisms form an active methane biofilter and help to counteract climate change.