Effect of pyoverdine supply on cadmium and nickel complexation and phytoavailability in hydroponics

• Published in: Environmental science and pollution research international 2015-02, Vol.22 (3), p.2106-2116
• Main Authors: Ferret, C, Cornu, J. Y, Elhabiri, M, Sterckeman, T, Braud, A, Jezequel, K, Lollier, M, Lebeau, T, Schalk, I. J, Geoffroy, V. A
• Format: Article
• Language: English
• Subjects: Analysis; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Bacteria; Biodegradation, Environmental; Bioremediation; Cadmium; Cadmium - chemistry; Cadmium - isolation & purification; Cadmium - metabolism; chelating agents; Contaminants; E coli; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Environmental Pollutants - chemistry; Environmental Pollutants - isolation & purification; Environmental Pollutants - metabolism; Environmental Sciences; Hydroponics; Internet resources; Investigations; Iron; Lycopersicon esculentum - drug effects; Lycopersicon esculentum - growth & development; Lycopersicon esculentum - metabolism; Lycopersicon esculentum - microbiology; Metals; Microorganisms; Nickel; Nickel - chemistry; Nickel - isolation & purification; Nickel - metabolism; Oligopeptides - biosynthesis; Oligopeptides - pharmacology; Phytoremediation; Plant Roots - metabolism; Pollution control; Pollution monitoring; Pseudomonas aeruginosa; Pseudomonas aeruginosa - metabolism; Research Article; siderophores; Siderophores - biosynthesis; Siderophores - pharmacology; Silicates - chemistry; smectite; Soil - chemistry; Soil contamination; Speciation; Studies; Waste Water Technology; Water Management; Water Pollution Control
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-014-3487-2

Siderophores are chelators with a high selectivity for Fe(III) and a good affinity for divalent metals, including Cd(II) and Ni(II). Inoculation with siderophore-producing bacteria (SPB) has thus been proposed as an alternative to chelator supply in phytoremediation. Accurate assessments of the potential of this association require a dissection of the interaction of siderophores with metals at the soil–root interface. This study focuses on pyoverdine (Pvd), the main siderophore produced by Pseudomonas aeruginosa. We first assessed the ability of Pvd to coordinate Ni(II). The stability constant of Pvd–Ni(II) (log Kᴸ′ᴺⁱ = 10.9) was found to be higher than that of Pvd–Cd(II) (log Kᴸ′Cᵈ = 8.2). We then investigated the effect of a direct supply of Pvd on the mobilization, speciation, and phytoavailability of Cd and Ni in hydroponics. When supplied at a concentration of 50 μM, Pvd selectively promoted Ni mobilization from smectite. It decreased plant Ni and Cd contents and the free ionic fractions of these two metals, consistent with the free ion activity model. Pvd had a more pronounced effect for Ni than for Cd, as predicted from its coordination properties. Inoculation with P. aeruginosa had a similar effect on Ni phytoavailability to the direct supply of Pvd.