Applied Microbiology and Biotechnology

, Volume 79, Issue 3, pp 499–510

In situ bacterial colonization of compacted bentonite under deep geological high-level radioactive waste repository conditions

Environmental Biotechnology

DOI: 10.1007/s00253-008-1436-z

Cite this article as:
Chi Fru, E. & Athar, R. Appl Microbiol Biotechnol (2008) 79: 499. doi:10.1007/s00253-008-1436-z
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Abstract

Subsurface microorganisms are expected to invade, colonize, and influence the safety performance of deep geological spent nuclear fuel (SNF) repositories. An understanding of the interactions of subsurface dwelling microbial communities with the storage is thus essential. For this to be achieved, experiments must be conducted under in situ conditions. We investigated the presence of groundwater microorganisms in repository bentonite saturated with groundwater recovered from tests conducted at the Äspö underground Hard Rock Laboratory in Sweden. A 16S ribosomal RNA and dissimilatory bisulfite reductase gene distribution between the bentonite and groundwater samples suggested that the sulfate-reducing bacteria widespread in the aquifers were not common in the clay. Aerophilic bacteria could be cultured from samples run at ≤55°C but not at ≥67°C. Generally, the largely gram-negative groundwater microorganisms were poorly represented in the bentonite while the gram-positive bacteria commonly found in the clay predominated. Thus, bentonite compacted to a density of approximately 2 g cm−3 together with elevated temperatures might discourage the mass introduction of the predominantly mesophilic granitic aquifer bacteria into future SNF repositories in the long run.

Keywords

Clay bufferSpent nuclear fuelSubsurfaceÄspöGranitic aquifersGroundwater

Copyright information

© Springer-Verlag 2008

Authors and Affiliations

  1. 1.Department of Cell and Molecular BiologyGöteborg University SwedenGothenburgSweden
  2. 2.Center for Ecology, Conservation and Evolution, School of Environmental SciencesUniversity of East AngliaNorwichEngland