Immobilization of uranium in biofilm microorganisms exposed to groundwater seeps over granitic rock tunnel walls in Olkiluoto, Finland

A spectroscopic study on U(VI) biomineralization in cultivated Pseudomonas fluorescens biofilms isolated from granitic aquifers

“…In contrast, P. fluorescens biofilms immobilized uranium by biomineralization. In these biofilms, bacteria were probably able to promote phosphatase activity resulting in the formation of meta-autunite, probably intracellularly as described in biofilms from the underground rock characterization facility tunnel ONKALO in Finland (Krawczyk-Bärsch et al 2012). The authors consider the possibility that meta-autunite minerals may have been formed in addition in the biofilm components, such as EPS.…”

“…Inorganic phosphate (H 2 PO 4 − ) is released from the cellular polyphosphate and forms strong complexes with uranium in the cytoplasm of some microorganisms. In a recent work, needle-shaped crystals of meta-autunite were determined in small rod-shaped microorganisms of a biofilm from the underground rock characterization facility tunnel ONKALO in Finland by means of energy-filtered transmission electron microscopy (EF-TEM), and electron energy-loss spectroscopy (EELS) studies after uranium sorption experiments with an initial uranium concentration of 0.04 mM (Krawczyk-Bärsch et al 2012). In microorganism strains isolated from extreme habitats, such as uranium waste piles and groundwater from radioactive waste depositories, the formation of polyphosphate-mediated autunite or meta-autunite as electron-dense granules was described in Merroun et al (2006).…”

“…In addition, the spectra of the aqueous uranyl carbonate species Ca 2 UO 2 (CO 3 ) 3 and UO 2 (CO 3 ) 3 4− were obtained for comparison. The results were compared with the luminescence properties of the aqueous uranyl carbonate complexes, described in Krawczyk-Bärsch et al (2012) and Steudtner et al (2011), respectively. The obtained luminescence spectra of the Ca 2 UO 2 (CO 3 ) 3 and UO 2 (CO 3 ) 3 4− species display band positions similar to those found in our studied uraniumcontaminated nutrient medium (Fig.…”

Geological repositories: scientific priorities and potential high-technology transfer from the space and physics sectors

“…Wouters et al, 2013). Near geological repositories, a variety of microbial metabolisms may be involved in changing the chemical speciation of elements and their mobility through the subsurface (Lloyd and Renshaw, 2005;Krawczyk-Barsch et al, 2012), or in affecting the performance engineered barriers, or in enhancing canister corrosion, concrete deterioration and the structure and performance of bentonite buffer materials used in nuclear waste disposal scenarios (Masurat et al, 2010;Pedersen, 2010), thereby affecting the performance of the engineered barriers and their functions (isolation and containment). Microorganisms and their activity can also change the transport properties of the host rocks of interest e.g.…”

Luminescence spectroscopy as versatile probes for chemical diagnostics on the solid–liquid interface

“…The application of TRLFS for the interaction of lathanide and actinide ions with microorganisms and biofilms has been an active research topic for decades [39][40][41][42]. Herein, the recent progresses in this field are briefly mentioned.…”