Bacteria derived bioactive compounds: A valuable tool for the electrochemical detection of arsenic (III) ions in contaminated water

Le résumé fourni par la source

A simple, fast and cost-effective electrochemical approach is here reported for the selective and quantitative detection of arsenic (III) ions in water starting from bacteria derived bioactive compounds . The exopolysaccharide (EPS B3-15) produced by the thermophilic, heavy metal tolerant Bacillus licheniformis B3-15, and the biosurfactant obtained from Bacillus horneckiae SBP3 (BS- SBP3) were used as sensitive elements for the electrochemical detection of As 3+ due to their known recognition abilities towards this toxic ion, their thermophilic properties and stability in harsh conditions. The covalent functionalization of screen-printed gold electrodes (SPGE) with these bioactive compounds demonstrated to be advantageous to selectively detect As 3+ in contaminated waters. Electrochemical measurements, performed for the developed sensors SPGE-EPS-B3-15 and SPGE-BS- SBP3, at the normal range of pH in surface water systems (6.5–8.5) demonstrated a higher sensitivity towards As 3+ with respect to the bare electrode, also in the presence of other competing ions, such as Al 3+ , Bi 3+ , Ni 2+ and Pb 2+ ,with very low limits of detection (0.19 nM for SPGE-EPS-B3-15 and 0.03 nM for SPGE-BS- SBP3), which are below the legal limits for these heavy metal ions in drinking water (10 μg/L). The reported sensitivity was 1.8 µA nM −1 cm −2 for SPGE-EPS-B3-15 and 17.5 µA nM −1 cm −2 for SPGE-BS- SBP3. The preferred detection abilities of the chosen bioactive compounds towards As 3+ ions have been also confirmed by complete conformational analysis, using a combination of Molecular Dynamics (MD) and Density Functional Theory (DFT) studies.

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