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 human gut harbors 100 trillion bacteria, most of which present in the colon. Bile acids are important biological compounds synthetized by the liver and transformed by microorganisms in the intestinal tract. One of the major bile acid transformations is the dehydroxylation at the C7 position and occurs in the colon. This 7-dehydroxylation is important for a number of biological functions including resistance against Clostridium difficile infections 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. The goal of this research project is to investigate the microbiology of these organisms including their sporulation and germination behavior, their metabolism in order to better understand the role of these organisms in the gut and their interactions with the host.