Browsing by Author "Malik, V"

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    Green mycosynthesis of silver nanoparticles exhibiting antimalarial activity
    (2024-07) Shankar, A; Kaushik, N; Kumar, V; Malik, V; Singh, D
    In the present study, different parameters, affecting the growth of Thermomyces lanuginosus BJMDU1 and extracellular synthesis of silver nanoparticles (AgNPs), were studied. Culture extract of thermophilic mould Thermomyces lanuginosus BJMDU1 showed potential in green synthesis of silver nanoparticles when the fungus was grown in a sucrose yeast extract medium (pH 8.0) at 45°C. Mycosynthesis of AgNPs was enhanced in the presence of light using 2 mM AgNO3 and 200 µl of culture extract at 50°C. The reaction parameters significantly improved the synthesis of AgNPs. Techniques like UV-Vis & FT-IR spectroscopy, X-ray diffraction, transmission electron microscopy and dynamic light scattering were used to characterise AgNPs. Biogenic nanoparti cles showed an absorption peak at 430 nm having 80 nm size. Biogenic AgNPs showed potent antibacterial and antiplasmodial activity with no haemolysis up to 40 µg/ml. The p-nitrophenol was catalytically reduced to p-aminophenol by AgNPs. Therefore, green mycosynthesised AgNPs could be used in the therapeutics and remediation of environmental pollutants.
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    Sporotrichum thermophile culture extract-mediated greener synthesis of silver nanoparticles: Eco-friendly functional group transformation and anti-bacterial study
    (2020-10) Shankar, A; Kumar, V; Kaushik, N; Kumar, A; Malik, V; Singh, D; Singh, B
    Thermophilic mould Sporotrichum thermophile BJTLRMDU7 played the role in greener synthesis of the silver nanoparticles (AgNPs) extracellularly using silver nitrate. The change in colour from transparent to dark brown primarily indicated the formation of AgNPs due to reduction of Ag (I) ions to Ag by the fungal culture extract. Nanoparticles synthetic process was optimized using “one variable at a time” approach. Sucrose containing medium having pH 8.0 supported the synthesis of AgNPs by the mould at 45 C. Furthermore, presence of light significantly accelerated the formation of silver nanoparticles. AgNPs were characterized by various techniques like UV–vis & FT-IR spectroscopy, dynamic light scattering (DLS) and X-ray diffraction (XRD). Appearance of a band at 426 nm in UV–vis spectrum revealed the reduction of Ag(I) ions to Ag (0) by mould’s culture filtrate. DLS data showed that AgNPs bear an average size of 70 nm, while XRD data revealed particle size of 40 nm. The application of AgNPs with their functional group transformation has successfully reduced p-nitrophenol into p aminophenol in an eco-friendly manner in the presence of light and NaBH4. Further, the synthesized AgNPs showed anti-bacterial potential against Gram positive and Gram negative bacteria.