The safety of nuclear waste repositories in the Swiss concept relies on engineered barrier systems in addition to the natural barrier (a suitable rock formation, 600 meters below the surface). Bentonite MX-80 (a natural clay) will be used as one of the engineered barriers. Currently, the Environmental Microbiology Laboratory (EML) is exploring the possibility to exploit beneficial effects of naturally occurring microbes in the bentonite and in the host rock while avoiding their negative effects. We want to find optimal design conditions where high microbial activity consumes hydrogen gas.
The gut microbiome harbours an incredibly wide diversity of bacteria, archaea, virus and eukaryotes, most of which still remains unexplored. Bile acids are important biological compounds synthetised in the liver and transformed by microorganisms in the intestinal tract. One of the major bile acid transformations is the dehydroxylation at the C7 position which occurs in the colon. This 7-dehydroxylation is important for a number of biological functions including immunity and glucose homeostasis. Thus, it is critical for the host to possess these 7-dehydroxylating bacteria among its gut microorganisms. However, these bacteria are very poorly characterized, their abundance is reported to be very low, which contrasts with the importance of bile acids for the host organism. The goal of this research project is to investigate the microbiology of these organisms with particular focus on their diversity and their 7-dehydroylation metabolic activity in order to better understand the role of these organisms in the gut and their interactions with the host.