Laccase oxidizes iodide to molecular iodine or hypoiodous acid, both of which are easily incorporated into natural soil organic matter. In this study, iodide sorption and laccase activity in 2 types of Japanese soil were determined under various experimental conditions to evaluate possible involvement of this enzyme in the sorption of iodide. Batch sorption experiment using radioactive iodide tracer ((125)I(-)) revealed that the sorption was significantly inhibited by autoclaving (121 °C, 40 min), heat treatment (80 and 100 °C, 10 min), γ-irradiation (30 kGy), N(2) gas flushing, and addition of reducing agents and general laccase inhibitors (KCN and NaN(3)). Interestingly, very similar tendency of inhibition was observed in soil laccase activity, which was determined using 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) as a substrate. The partition coefficient (K(d): mL g(-1)) for iodide and specific activity of laccase in soils (Unit g(-1)) showed significant positive correlation in both soil samples. Addition of a bacterial laccase with an iodide-oxidizing activity to the soils strongly enhanced the sorption of iodide. Furthermore, the enzyme addition partially restored iodide sorption capacity of the autoclaved soil samples. These results suggest that microbial laccase is involved in iodide sorption on soils through the oxidation of iodide.
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Chemosphere
December 2024
Division of Sustainable Resources Engineering, Faculty of Engineering, Hokkaido University, Sapporo, 060-8628, Hokkaido, Japan.
At the Fukushima Daiichi Nuclear Power Station (FDNPS), continuous water circulation cools fuel debris, leading to the presence of radionuclides such as Sr-30, Cs-137, and I-129 in the cooling water. These radionuclides are adsorbed and co-precipitated by various materials. Among them, I-129 is a key radionuclide for safety assessment during the final disposal of adsorbent and co-precipitation materials, owing to its long half-life and poor sorption.
View Article and Find Full Text PDFACS Earth Space Chem
February 2024
Pacific Northwest National Laboratory, Richland, Washington 99354, United States.
Radioiodine (I) poses a potential risk to human health and the environment at several U.S. Department of Energy sites, including the Hanford Site, located in southeastern Washington State.
View Article and Find Full Text PDFChemphyschem
March 2024
Department of Physical and Physico-chemical Methods of Mineral Processing, Institute of Geotechnics SAS, Watsonova 45, 04001, Kosice, Slovak Republic.
A series of nanosilica/AgI composites was synthesized by in situ reactions between silver nitrate and ammonium iodide deposited on the nanosilica surface using the gas-phase solvate-stimulated mechanosorption modification (GSSMSM) under both dry and wet conditions. The characterization of the synthesized materials was performed by X-ray diffraction (XRD), SEM/EDX (Scanning Electron Microscopy-Energy Dispersive X-ray), thermogravimetric (TGA) and gas sorption methods. As a result of the mechanosorption modification of nanosilica, the bulk density of the samples synthesized in the dry and wet medium increases from 45 g/l for initial nanosilica to 249 g/l and 296 g/l for the modified samples, respectively.
View Article and Find Full Text PDFAdv Sci (Weinh)
January 2024
Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo, 152-8550, Japan.
ACS Infect Dis
December 2023
Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur-208016, Uttar Pradesh, India.
Survival of foodborne Gram-negative bacteria during osmotic stress often leads to multidrug resistance development. However, despite the concern, how osmoadaptation alters drug penetration across the Gram-negative bacterial cell envelope has remained inconclusive for years. Here, we have investigated drug permeation and accumulation inside hypo-osmotically shocked .
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