Shortening the sulfur cell cycle by a green approach for bio-production of extracellular metalloid-sulfide nanoparticles

Abstract

In the present study, a new approach was introduced regarding the extracellular synthesis of selenium sulfide micro/nano-particles using Saccharomyces cerevisiae in different ammonium sulfate supplementation and in the presence of sodium selenosulfate precursors (S1) and a blend of selenous acid and sodium sulfite (S2). In S1, only cell supernatant exposed to ammonium sulfate was able to reduce sodium selenosulfate. Whereas, in S2, cell supernatant in both pre-conditions of with or without ammonium sulfate (S2 + or S2−) were able to reduce selenous acid and sodium sulfite. Electron microscopy, also indicated that selenium sulfide NPs were successfully synthesized with average size of 288 and 332 nm for S2 + and S2− in SEM and 268 and 305 nm in TEM. Additionally, elemental mapping by energy-dispersive x-ray analysis confirmed the presence of sulfur/selenium elements in the particles in a proportion of 24.50 and 23.31 for S2− and S2 + , respectively. The mass spectrometry indicated the probability of Se2S2, SeS1.1, Se2, Se, SeS5, SeS3, Se3S5/Se5, Se3/SeS5, Se6, Se4/SeS7, Se2.57S5.43/Se2S2 and Se4S/Se2S6 molecules for S2 + and of Se, Se2, Se3S5/Se5, Se6 and Se4 species for S2−. In FTIR spectra, primary (i.e. 1090–1020 and 1650–1580 cm−1) and secondary (1580–1490 cm−1) amine bands duly confirmed the protein corona around the NPs.