Siderophore production in the presence of silicates by Pseudomonas aeruginosa

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Microbially-mediated glass dissolution and sorption of metals by Pseudomonas aeruginosa cells and biofilm.

A basaltic glass and a vitrified bottom ash were incubated at 25 degrees C in a growth medium (based on casaminoacids) inoculated with Pseudomonas aeruginosa. Bacterial growth and mineral concentrations in different compartments (bacterial cells, growth medium and biofilm) were monitored in short-term (3 days), and long-term experiments involving repeated renewals of the culture medium during 174 days. In short-term experiments, while the concentration of iron increased in the presence of bacteria, a decrease in Ni and Zn was observed in the growth medium compared to the sterile condition. During long-term experiments, such differences gradually decreased and disappeared after 78 days. On the contrary, iron concentration remained higher in the biotic condition compared to the sterile one. Bacterial growth resulted within a few days in the formation of a biofilm, which lead to the cementation of the altered glass grains. Most of the constituents of the glass (Si, Mg, Fe, Ti, Ba, Co, Zn, Cu, Ni and Cr) were found in the biofilm, while the chemical composition of the bacterial cells was very different

Influence of bacteria on lanthanide and actinide transfer from specific soil components (humus, soil minerals and vitrified municipal solid waste incinerator bottom ash) to corn plants: Sr-Nd isotope evidence.

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Interactions between Municipal Solid Waste Incinerator bottom ash and Pseudomonas aeruginosa.

International audienc

Contrasting effects of pyoverdine on the phytoextraction of Cu and Cd in a calcareous soil

International audienceEnhanced metal phytoextraction by the use of siderophore-producing bacteria (SPB) has received a lot of attention in the past decade. Bacterial siderophores are able to bind a wide range of metals other than iron and thus should enhance their phytoavailability in contaminated matrices. However, the impact of bacterial siderophores in the soil-plant transfer of metals is not yet fully elucidated, as underlined by the opposing results reported in the literature regarding the efficiency of coupling phytoextraction with bioaugmentation by SPB. The present study focuses on one bacterial siderophore, the pyoverdine (Pvd), produced by Pseudomonas aeruginosa. The coordination properties of Pvd towards Cd(II) and Cu(II) were determined and the effect of Pvd supply was assessed on (i) the mobility (CaCl2 extractions), (ii) the phytoavailability (DGT measurements) and (iii) the phytoextraction of Cd and Cu, in a calcareous soil. The stability constant of Pvd-Cu (K-LCu = 10(20.1)) was found much higher than that of Pvd-Cd (K-Lcd = 10(8.2)). The major finding was the agreement observed between Pvd coordination properties and Pvd impact on metals phytoextraction. Pyoverdine, supplied at 250 mu mol kg(-1) soil, enhanced the mobility, the phytoavailability and the phytoextraction of Cu while the fate of Cd was not affected. All these results were compared to those reported for chelate-assisted phytoextraction. Their relevance in using SPB for phytoremediation is discussed