Diana S. Raie, Ioannis Tsonas, Stefanos Mourdikoudis, Evangelia Delli, Antonios Makridis, Lena Ciric and Nguyen Thi Kim Thanh
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引用次数: 0
Abstract
Shewanella oneidensis (S. oneidensis) MR-1 is a metal-reducing bacterium that can bio-reduce the carcinogenic hexavalent chromium (Cr6+) to a less toxic trivalent form (Cr3+). The bacteriocidal effect of Cr6+ challenges the above bio-reduction process. This work aims to illustrate the protective role of manganese ferrite nanoparticles (Mn0.2Fe2.8O4 NPs) to S. oneidensis MR-1 bacteria during the bio-reduction of Cr6+. Nanostructures were characterised by transmission electron microscopy (TEM) and X-ray diffraction (XRD). The interaction between S. oneidensis MR-1, Cr6+ and Mn0.2Fe2.8O4 NPs was monitored by X-ray photoelectron spectroscopy (XPS), which helped to unravel the oxidation states of Cr. The XPS analysis provided key insights into the oxidation states of Mn and Fe, confirming the redox interactions facilitating Cr6+ reduction. Mn0.2Fe2.8O4 NPs boosted the detoxification of the removed Cr6+ by 2.1 and 1.4 times compared to using S. oneidensis MR-1 alone and NPs alone, respectively. Scanning electron microscopy (SEM) imaging evaluated the changes in the morphology of bacterial cells. After exposure to Cr6+, S. oneidensis MR-1 cells revealed their inability to produce nanofibers, which are electrically conductive bacterial appendages. Yet, Mn0.2Fe2.8O4 NPs provoked the formation of bacterial nanofibers. These findings highlight the potential of Mn0.2Fe2.8O4 NPs for enhancing the bioremediation of Cr6+ contaminated environments.
期刊介绍:
Environmental Science: Nano serves as a comprehensive and high-impact peer-reviewed source of information on the design and demonstration of engineered nanomaterials for environment-based applications. It also covers the interactions between engineered, natural, and incidental nanomaterials with biological and environmental systems. This scope includes, but is not limited to, the following topic areas:
Novel nanomaterial-based applications for water, air, soil, food, and energy sustainability
Nanomaterial interactions with biological systems and nanotoxicology
Environmental fate, reactivity, and transformations of nanoscale materials
Nanoscale processes in the environment
Sustainable nanotechnology including rational nanomaterial design, life cycle assessment, risk/benefit analysis