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Research Publications (Applied Sciences)

Permanent URI for this collectionhttp://ir-dev.dut.ac.za/handle/10321/213

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Author: search.filters.author.Veerappa Lakshmaiah, VasanthaHas files: Yes

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    Bio-decolorization and degradation of reactive blue 222 by a novel isolate Kucoria marina CU2005
    (Association of Biotechnology and Pharmacy, 2023-01-30) Veerappa Lakshmaiah, Vasantha; Krishna, Suresh Babu Naidu; S More, Sunil; K Jayanna, Shobha
    In this study, a novel bacterial strain, Kucoria marina CU2005, was isolated and identified using 16S rRNA gene sequencing from an industrial wastewater sludge sample capable of degrading Reactive Blue 222 (RB222) dye. Batch mode bio stimulation studies were performed with minimal salt media to optimize key physiological parameters for effective decolorization of RB222. When cultured at 35 °C and pH 7 under static conditions, this bacterium decolorized 82 percent of the dye after 24 hours. Decolorization was monitored using UV-vis spectrophotometry. Isolate’s ability to decolorize the complex dye was attributed to its degradation potential rather than a passive surface adsorption. FTIR, HPLC, GC-MS studies were used to confirm microbial dye metabolism. The results indicated breakdown of dye upon decolorization as some peaks were shifted and generation of aromatic amine for monosubstituted benzene ring as intermediates of dye degradation in decolorized solutions. This study has shown the potential of Kucoria marina CU2005 to decolorize RB222 dye at a better pace and efficiency than previously reported bacterial strains. Thus, we propose that our isolated strain can be utilized as a potential dye decolorizer in environmental biotechnology as effluent treatment for decolorization of RB 222.
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    Fungi-templated silver nanoparticle composite: synthesis, characterization, and its applications
    (MDPI AG, 2023-02-06) Joy, Francis; Devasia, Jyothis; Nizam, Aatika; Veerappa Lakshmaiah, Vasantha; Krishna, Suresh Babu Naidu; Krishna, Suresh Babu Naidu; Anthony William, Coleman
    The self-assembly of nanoparticles on living bio-templates is a promising synthetic methodology adopted for synthesizing nano/microstructures with high efficiency. Therefore, the method of bio-templating offers various advantages in controlling the geometries of nano/microstructures, thereby increasing the efficiency of the synthesized material towards various functional applications. Herein, we utilized a filamentous fungus (Sclerotium rolfsii) as a soft bio-template to generate silver nanoparticle (AgNP) microtubules adhering to the fungal hyphae. The resulting composite combines the unique properties of silver nanoparticles with the biological activity of the fungi. The 3D fungal hyphae–silver nanoparticle (FH-AgNP) composite was characterized using SEM, elemental analysis, and the X-ray diffraction technique. Additionally, to highlight the functional application of the synthesized composite, dye degradation studies of methylene blue under visible light was effectuated, and a percentage degradation of 67.86% was obtained within 60 min, which highlights the potent catalytic activity of FH-AgNPs in dye degradation. Further, the antibacterial study of the composite was carried out against the bacterium Escherichia coli, and it was found that 200 µg of the composite exhibited maximum antibacterial properties against Gram positive (Staphylococcus aureus) and Gram negative (Escherichia coli) bacteria. Overall, fungi-templated silver nanoparticle composites are a promising area of research due to their combination of biological activity and unique physical and chemical properties.