Flocculating Activity of Cross-linked Poly-γ-Glutamic Acid against Bentonite and Escherichia coli Suspension Pretreated with FeCl_3 and Its Interaction with Fe^<3+>(ENVIRONMENTAL BIOTECHNOLOGY)

概要

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Cross-linked poly-γ-glutamic acid (C-L γ-PGA) at 5 μg/ml flocculated bentonite suspension pretreated with polyaluminum chloride (PAC) at 2 μg/ml Al^<3+>-PAC to a transparency of approximately 30% after 30min and more than 90% after 4 h, while Al^<3+> concentration in the upper phase of the suspension decreased with incubation time. When pretreated with FeCl_3 at 16 μg/ml Fe^<3+>-FeCl_3, similar results were obtained. In the case of Escherichia coli suspension, the combination of C-L γ-PGA and FeCl_3 demonstrated a more marked flocculating activity with a satisfactory transparency occurring after 30min of treatment, accompanied by a decrease in residual Fe^<3+> concentration. In the above two suspensions pretreated with FeCl_3, small visible floats appeared in the early stage of incubation. These floats were found to be due to the direct interaction between FeCl_3 and C-L γ-PGA, indicating the formation of a water-insoluble complex. After allowing the suspension to stand for a long time, elemental analysis and inductively coupled plasma spectroscopy of the precipitates produced suggested that not only the complex was formed due to the interaction between Fe^<3+> in FeCl_3 and COO^- in the C-L γ-PGA molecule, but also Fe_2O_3 and Fe(OH)_3 might be entrapped in this complex. This could be applied to scavenge metal ions including Fe^<3+> from polluted water.
社団法人日本生物工学会の論文
2005-08-25