Sustainable green approach to synthesize Fe 3 O 4 /α-Fe 2 O 3 nanocomposite using waste pulp of Syzygium cumini and its application in functional stability of microbial cellulases

Synthesis of nanomaterials following green routes have drawn much attention in recent years due to the low cost, easy and eco-friendly approaches involved therein. Therefore, the current study is focused towards the synthesis of Fe ₃O ₄/α-Fe ₂O ₃ nanocomposite using waste pulp of Jamun (Syzygium cumini) and iron nitrate as the precursor of iron in an eco-friendly way. The synthesized Fe ₃O ₄/α-Fe ₂O ₃ nanocomposite has been extensively characterized through numerous techniques to explore the physicochemical properties, including X-ray diffraction, Fourier transform infrared spectroscopy, Raman spectroscopy, Ultraviolet-Vis spectroscopy, field emission scanning electron microscope, high resolution transmission electron microscope and vibrating sample magnetometer. Further, efficiency of the Fe ₃O ₄/α-Fe ₂O ₃ nanocomposite has been evaluated to improve the incubation temperature, thermal/pH stability of the crude cellulase enzymes obtained from the lab isolate fungal strain Cladosporium cladosporioides NS2 via solid state fermentation. It is found that the presence of 0.5% Fe ₃O ₄/α-Fe ₂O ₃ nanocomposite showed optimum incubation temperature and thermal stability in the long temperature range of 50–60 °C for 15 h along with improved pH stability in the range of pH 3.5–6.0. The presented study may have potential application in bioconversion of waste biomass at high temperature and broad pH range.