Production of silica nanoparticles from rice husk and rice straw by fungal-mediated biotransformation using Pleurotus florida

Agriculture waste needs proper management for a balanced ecosystem. The management of such waste can be used to produce bioenergy, conserving nonrenewable resources and producing nanoparticles. This study reports the utilization of rice husk and straw in an innovative bio-transformative route to isolate silica nanoparticles (SiNPs). The rice husk and straw were initially subjected to mushroom cultivation, followed by the extraction of SiNPs from the spent substrates. The SiNPs obtained from the raw straw and husk samples and from the spent substrates were characterized by using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Fourier transforms infrared spectroscopy (FTIR), and energy-dispersive X-ray spectroscopy (EDS). FESEM results showed that the particle size of SiNPs lies between 15 and 30 nm and 25 and 30 nm for rice husk and straw, respectively. The mushroom yield of Pleurotus florida was 26.9% and 53.1% for rice husk and rice straw, respectively. The total yield of SiNPs from spent husk and straw was 67.5% and 26.2%, respectively. The nanoparticles derived from rice husk and straw inhibited the growth of Staphylococcus aureus (59.9 ± 1.3% and 65.3 ± 2.4%, respectively) and Escherichia coli (68.5 ± 2.8% and 70.1 ± 2.5%) at a 100 mg/ml SiO₂ concentration. Present study results suggest that raw husk and straw and spent husk and straw could serve as a potential source for the production of SiNPs.