Effect of salinity and pH on cobalt biosorption by the estuarine microalga Chlorella saliva

Geoffrey W. Garnham, Geoffrey A. Codd, Geoffrey M. Gadd

    Research output: Contribution to journalArticlepeer-review

    25 Citations (Scopus)

    Abstract

    Accumulation of cobalt (60Co) by the estuarine microalga Chlorella salina has been characterized. At cobalt concentrations ranging over 3.125-100 μM, a significant amount of cobalt was bound within 1 min. This was metabolism-independent and unaffected by incubation in light or dark conditions. This initial rapid phase of biosorption was followed by a slower phase of uptake which was apparently active and inhibited by incubation in the dark, or by the uncoupler dinitrophenol and the respiratory and photosynthetic inhibitor potassium cyanide in the light. For cells suspended in 10 mM Taps pH 8, cobalt biosorption followed a Freundlich adsorption isotherm. However, in the presence of 0.5 M NaCl, biosorption deviated from the Freundlich model because of competition by Na+. Cobalt biosorption was decreased by increasing concentrations of Na+, decreasing pH and the presence of Cs+, Li+, Rb+, Zn2+. Mn2+ and Sr2+ (added as chlorides). This was a result of competition between Co2+ and the other cations, including H+, for available binding sites on the cell wall and was confirmed by increased desorption of cobalt by solutions of low pH or high salinity. Increasing cell density resulted in increased removal of cobalt from solution but decreased the specific amount of cobalt taken up by the cells.

    Original languageEnglish
    Pages (from-to)151-157
    Number of pages7
    JournalBiology of Metals
    Volume4
    Issue number3
    DOIs
    Publication statusPublished - Sept 1991

    Keywords

    • Co
    • Biosorption
    • Cell density
    • Chlorella salina
    • pH
    • Salinity

    ASJC Scopus subject areas

    • General Biochemistry,Genetics and Molecular Biology
    • General Agricultural and Biological Sciences

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