Mycogenic synthesis of iron nanoparticles using thermophilic mould Myceliophthora thermophila and their applicability in environmental remediation

Culture extract of thermophilic mould Myceliophthora thermophila BJTLRMDU7 played important role in the green synthesis of iron nanoparticles (FeNPs) using ferrous sulphate (FeSO4). The mould was grown in potato dextrose broth (PDB) at 45 °C and 200 rpm for 72 h. A colour change from transparent to reddish brown showed the synthesis of FeNPs due to the surface plasmon resonance by the fungal culture extract. The process for the synthesis of nanoparticles was optimized using different reaction conditions. Biogenic iron nanoparticles were synthesized maximally at 50 °C and pH 5.0 after 24 h using 2 mM salt solution and one ml culture extract. Furthermore, formation of iron nanoparticles was significantly accelerated in the presence of light. The absorption peak was maximum around 250–350 nm in UV–vis spectrum. The absorption peaks of Fourier-transform infrared spectroscopy (FTIR) at 619.99 cm−1, 793.57 cm−1, 882.32 cm−1, 1121.46 cm−1, 1627.71 cm−1, 2923.17 cm−1 and 3430.70 cm−1, indicated functional groups of active biomolecules involved in the synthesis of FeNPs. Atomic force microscopy (AFM) images of green synthesized iron nanoparticles indicated the average size of 80 nm, while X-ray diffraction (XRD) data revealed the crystalline nature of FeNPs. These FeNPs efficiently reduced p-nitrophenol (PNP) into p-aminophenol (PAP), which was further confirmed by thin layer chromatography. Biogenic FeNPs showed 96 and 35 % decolourization of bromphenol blue and malachite green, respectively. Further, addition of H2O2 enhanced the decolourization of malachite green up to 96 %. Biogenic FeNPs synthesized from culture extract of a thermophilic mould have been found effective in remediation of environmental pollutants released from various industries.