Investigation of the Microbial Communities of Bentonites from Two Different Repositories under Different Temperature of Incubation

Abstract

Bentonite clays have a large specific surface area and a large Vume of pore space, which determines their high sorption capacity and allows them to be used as one of the barriers in the construction of deep geological repositories (DGR). It is expected that DGR will function for thousands of years, so the problem of forecasting changes that may occur during this time is relevant. During the functioning of DGR, bentonites can change their properties due to microbiological effects. In this work was analyzed the microbial community structure of two bentonites from 10th Khutor and Taganskoye disposal at different temperatures (25 and 60°C) of incubation. In bentonite from the 10th Khutor deposit, 10 phyla and 92 genera of bacteria were identified during incubation at 60°С, while 12 phyla and 94 genera were identified during incubation at 25°С. In bentonite from the Taganskoye deposit, 14 phyla and 87 genera were identified during incubation at 60°С, and 15 phyla and 123 genera were identified during incubation at 25°С. Samples were dominated with bacteria of Proteobacteria and Firmicutes phyla. It was concluded that is the main factor influencing the formation of the microbial in the studied bentonites community is temperature, and not the chemical and mineral composition of examined bentonites.