An indigenous iron-reducing microbial community from MX80 bentonite - A study in the framework of nuclear waste disposal

Highly compacted MX80 bentonite has been selected as the engineered buffer and backfill material in several proposed concepts for long-term deep geological storage of nuclear waste . Iron-reducing bacteria reduce Fe (III) to (II) some are adapted high temperatures desiccated environments, keeping with periods less habitable conditions within repository. In one potential UK repository concept, iron from carbon steel canisters may contribute an iron-rich environment at clay-canister interface. This could lead changes mineralogy iron-content due variation redox state solubility, which turn alter geomechanical properties clay. To investigate role iron-reducing this process enrichments were carried out both commercially available powder identify presence indigenous iron-interacting community Throughout these soluble, total, pH measured, subjected 16S rRNA analysis. Concentrations total peaked day 28 all enrichments; however, concentration was overall higher when accompanied by bacterial growth. soluble remained low throughout. gene sequencing revealed putative bacteria, well thermotolerant spore-forming species. The largely comprised firmicutes, including iron-reducers such Desulfosporosinus Therefore, inherently carries a viable microbial potentially interact structural present or other mineral components, canister. Various research shown that activity is unlikely bulk provided compaction maintained. importance highlighted finding here viable, robust functionally diverse clay be possible anyway edge sites interfaces where, locally, swelling pressures might not fully develop. • enriched Addition Shewanella oneidensis culture did facilitate reduction rates Firmicutes dominate Desulfitobacterium Fermenting produce energy sources sustain