Optimal synthesis conditions and characterization of selenium nanoparticles in Trichoderma sp. WL-Go culture broth

Selenium nanoparticles (SeNPs) was synthesized by a simple, environmentally benign SeO2-reduction process in Trichoderma sp. WL-Go culture broth and followed by filtration to obtain culture broth supernatant which was then characterized. The optimal conditions for the SeNPs synthesis were pH 8, inoculation time of SeO2 at 24 h and SeO2 concentration of 2 mM. The supernatant analysis with UV-vis indicated a visible peak at 550 nm whilst TEM showed the presence 20-220 nm spherical and pseudo-spherical Se particles. Furthermore, XRD analysis confirmed the crystalline structure of the SeNPs exhibiting diffraction peaks assigned as (100), (101) and (102) plane of the nanoparticles. FTIR analysis revealed the presence of functional groups of alkene, alkane and alcohol groups that might have participated in the SeNPs synthesis reactions. The SeNPs showed electrokinetic potential of -24.6 mV at pH 7.22 after washing. DLS analysis also indicated that the particles had an average particle size to of 147.1 nm. SDS-PAGE analysis of the supernatant also showed two protein peaks at similar to 19 kDa and similar to 15 kDa which might have served as reducing and capping agents. Selenium removal rate of 84.73% was achieved thus giving the bases for future research under diverse experimental conditions using Trichoderma sp. WL-Go.