Aims
Investigate the capability of Aspergillus brasiliensis ATCC 16404 to mycosynthesize Co3O4‐NPs.
Methods and Results
Mycelial cell‐free filtrate of A. brasiliensis ATCC 16404 was applied for mycosynthesis of Co3O4‐NPs. The preliminary indication for the formation of Co3O4‐NPs was the change in colour from yellow to reddish‐brown. One‐factor‐at a time‐optimization technique was applied to determine the optimum physicochemical conditions required for the mycosynthesis of Co3O4‐NPs and they were found to be: 72 h for reaction time, pH 11, 30°C, 100 rev min−1 for shaking speed in the darkness using 4 mmol l−1 of CoSO4.7H2O and 5·5% of A. brasiliensis dry weight mycelium (w/v). The mycosynthesized Co3O4‐NPs were characterized using various techniques: spectroscopy including UV/Vis spectrophotometry, dynamic light scattering (DLS), zeta potential measurement, energy‐dispersive X‐ray analysis, Fourier transform infrared spectroscopy and X‐ray diffraction; and vibrating sample magnetometry and microscopy including field emission scanning electron microscopy and high‐resolution transmission electron microscopy. Spectroscopic techniques confirmed the formation of Co3O4‐NPs and the microscopic ones confirmed the shape and size of the mycosynthesized Co3O4‐NPs as quasi‐spherical shaped, monodispersed nanoparticles with a nano size range of 20–27 nm. The mycosynthesized Co3O4‐NPs have excellent magnetic properties and exhibited a good antimicrobial activity against some pathogenic micro‐organisms.
Conclusion
Ferromagnetic Co3O4‐NPs with considerable antimicrobial activity were for the first time mycosynthesized.
Significance and Impact of the Study
The use of fungi as potential bionanofactories for mycosynthesis of nanoparticles is relatively a recent field of research with considerable prospects.