Intra and extra cellular biosynthesis of selenium nanoparticles by unicellular and filamentous selenium tolerant fungi

Hassan, Esraa Mohamed; Gharieb, Mohamed Medhat; Soliman, Azza Mahmoud

doi:10.21608/djs.2023.220345.1123

Intra and extra cellular biosynthesis of selenium nanoparticles by unicellular and filamentous selenium tolerant fungi

Document Type : Research and Reference

Authors

¹ Faculty of science, Menoufia university, Microbiology department

² Botany and microbiology department, Faculty of Science, Elmonofia University

³ Microbiology department, faculty of science, Menoufia university

10.21608/djs.2023.220345.1123

Abstract

Fifty fungal isolates (filamentous and uni cellular) were screened for their ability to reduce sodium selenite (Na2Seo3). Out of those, twenty eight isolates displayed positive results therefore they were screened for their ability to tolerate higher concentrations of sodium selenite for different incubation periods. The most active three isolates were characterized morphologically and physiologically. They were identified as Fusarium oxysporum, Rhodotorula mucilaginosa and Cryptococcus albidus on the bases of 18S RNA encoding gene. The Se reduction power of Fusarium oxysporum decreased by increasing the selenite concentration, it reached the maximum value 96.6% of 1mM concentration of sodium selenite with the net dry weight 7.7 mg/ml. However the reduction power of Rhodotorula mucilaginosa and Cryptococcus albidus reached the maximum value 99 & 98.8% of 5 & 7mM of sodium selenite with the net dry weight 7.2 & 6.6 mg/ml respectively. It was found that F. oxysporum reduced selenite extracellulary while both R. mucilaginosa and C. albidus reduced it intracellulary. The biosynthesized selenium particles were purified and dried at 40 °C, and characterized using UV- vis spectroscopic, Transmission electron microscopy and Fourier- Transform infrared Spectroscopy (FTIR) analysis, this is to confirm the selenium nanoparticles (Se-NPs) formation. Transmission electron microscopic images explained the formation of mono disperse spherical-selenium nanoparticles in the range of 14 –97 nm with spherical shape. In addition, the resonance peak appeared at 200- 300 nm which corresponds to the particle size of 14-97 nm. Fourier transform infrared spectroscopy confirmed the presence of a protein shell outside the nanoparticles.

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