Browsing by Author "Ahumibe, Nkenna Chinonyerem"

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    Influence of chelating agents and nickel on phenol utilization by pseudomonas species
    (Federal University of Technology, Owerri, 2016-08) Ahumibe, Nkenna Chinonyerem
    The effects of nickel and four chelating agents, trisodium citrate, ethylenediaminetetraacetic acid, tannic acid and potassium ferricyanide, at different concentrations in nutrient broth and a mineral salts medium supplemented with phenol, on the dehydrogenase activity of a Pseudomonas species, as well as the effects of nickel and trisodium citrate on phenol biodegradation were investigated. The results showed that the bacterium was sensitive to nickel with an observed half maximal inhibitory concentration (IC50) of 0.613 mM and 0.0017 mM in nutrient broth and mineral salts medium, respectively. Trisodium citrate and ethylene diaminetetraacetic acid were most efficient in reducing the inhibitory effect of nickel mwhile the effects of tannic acid and potassium ferricyanide were not very pronounced. Nickel inhibited phenol degradation by Pseudomonas sp. The addition of trisodium citrate stimulated 84 the growth rate of the bacterium but had no significant effect on phenol degradation rate. The progress of growth was described by the integrated Haldane model with kinetic constants of µm 0.0967 h-1, Ks 78.289 mg/l, and Ki 346.687 mg/l at 500 mg/l initial phenol concentration. Maximum specific growth rate (µm) decreased in the presence of nickel, and increased with trisodium citrate addition. The results of the study showed that chelating agents could mitigate nickel toxicity. Also, they suggest that trisodium citrate could be used as a possible carbon source in biodegradation studies.