Shedding light on the microbial dark matter with photons from Synchrotron radiation: structural biology of mesocosms by an explorative pipel

The microbial world is constantly shaping the planet by governing the carbon, nitrogen, and sulfur cycles. While recent developments in ¿omics¿ opened a window of the complexity of this world, it is still problematic to attribute a function to a gene product or predict enzymatic reactions simply from its sequence. Then, how can enzymes be studied from uncultivated microbes? In this proposal, we are using an explorative approach to open a new field: the structural elucidation of catabolic enzymes from microbial mesocosms. We will study two models, an anaerobic bioreactor containing a methane-degrading consortium, and a microbial community from wastewater treatment. As a proof of concept, we recently isolated, crystallized, and structurally characterized the methane-generating enzyme from an archaeon living in this activated sludge. Now, we will go beyond and isolate more enzymes of catabolic pathways from these "microbial dark matter", playing a key role in the carbon cycle.