Biosynthesis,characterization And Applications Of Selenium And Selenium Alloy Nanoparticles By Trichoderma Sp.WL-Go

Selenium nanoparticles?Se NPs?and lead selenide nanoparticles?PbSe NPs?were synthesized by a simple,environmentally benign reduction process with Trichoderma sp.WL-Go.Trichoderma sp.WL-Go are known to have strong growth activity and secrets large amounts of extracellular enzymes and metabolites with massive adsorption sites that are rich in redox proteins,polysaccharides and secondary metabolites.The synthetic non-metallic and semiconductor NPs showed high yield,and great dispersion.Se NPs synthesis was carried out in strain WL-Go culture and followed by filtration to obtain culture broth supernatant.The optimal conditions for the Se NPs 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 Se NPs 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 Se NPs synthesis reactions.The Se NPs 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 of 147.1 nm.SDS-PAGE analysis of the supernatant also showed two protein peaks at ¹9 kDa and ¹5 kDa which might have served as reducing or capping agents.The PbSe NPs were synthesized with the biomass of strain WL-Go in PBS buffer.Synthesis at pH 8 with 0.5 g biomass of strain WL-Go and?1:1?mM of SeO₂:Pb?NO₃?₂ were the optimal synthesis conditions.XRD and TEM analyses indicated that the PbSe NPs were cubic faced centered with sizes in the range of 10-30 nm.Alkane,alkene and the hydroxide functional groups served as reducing and capping agent for the NPs.The PbSe NPs reported a bandgap of 1.5 eV which is higher than the bulk PbSe.Raman spectrometry revealed a band at238 cm^-1 is a weak band with consistent trend of progressive breaking of Se-chains.The PL emission patterns were linked to the change in the concentration of charge carriers and recombination of photoexcited electrons and holes.By calculation,selenium removal rate of 84.73%was present in the broth supernatant.The Se NPs also showed its biocompatible activity towards gram-positive bacteria Arthrobacter sp.W1 and gram-negative bacteria E.coli BL21 and antioxidant activity to eliminate free radicals of 2,2-diphenyl-1-picrylhydrazyl?DPPH?up to 84.20%.The synthesized PbSe NPs served as catalysts for the investigation of the antioxidant activity using DPPH and photo degradation ability of rhodamine B dye?10 mg/L?.The results indicated that the NPs could eliminate up to88.60%of free radicals after adding 600 ug/mL NPs and could photodegrade 82%of rhodamine B in 30 min.Thus,these studies provide new knowledge and strategies for the future use of an environmentally benign bio-catalytic nanoparticles.The PbSe NPs showed an improved application performance over the synthesized Se NPs but both can efficiently eliminate free radicals and in treatment of persistent organic pollutants in wastewaters.