Accumulation of heavy metals by Pseudomonas fluorescens 4F39 was rapid and pH-dependent. The affinity series for bacterial accumulation of metal cations decreased in the order Ni>>Hg>U>>As>Cu>Cd>Co>Cr>Pb. Metal cations were grouped into those whose accumulation increased as the pH increased, with a maximum accumulation at the pH before precipitation (Ni, Cu, Pb, Cd, Co), and those whose maximum accumulation was not associated with precipitation (Cr, As, U, Hg). High Ni2+ accumulation was studied. Electron microscopy indicated that at pH 9, Ni2+ accumulated on the cell surface as needle and hexagon-like precipitates, whose crystalline structure was confirmed by electron diffraction analysis and corresponded to two different orientations of the nickel hydroxide crystals. Crystals on cells showed marked anisotropy by X-ray powder diffraction, which differentiated them from crystals observed in nickel solution at pH 10 and 11 and from commercial nickel hydroxide. Nickel biosorption by Pseudomonas fluorescens 4F39 was a microprecipitation consequence of an ion exchange. Journal of Industrial Microbiology & Biotechnology (2000) 24, 146–151.
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Received 22 June 1999/ Accepted in revised form 04 December 1999
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López, A., Lázaro, N., Priego, J. et al. Effect of pH on the biosorption of nickel and other heavy metals by Pseudomonas fluorescens 4F39. J Ind Microbiol Biotech 24, 146–151 (2000). https://doi.org/10.1038/sj.jim.2900793
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DOI: https://doi.org/10.1038/sj.jim.2900793