Selenite bioreduction and biosynthesis of selenium nanoparticles by Bacillus paramycoides SP3 isolated from coal mine overburden leachate

• Published in: Environmental pollution (1987) 2021-09, Vol.285, p.117519-117519, Article 117519
• Main Authors: Borah, Siddhartha Narayan, Goswami, Lalit, Sen, Suparna, Sachan, Deepa, Sarma, Hemen, Montes, Milka, Peralta-Videa, Jose R., Pakshirajan, Kannan, Narayan, Mahesh
• Format: Article
• Language: English
• Subjects: Bacillus paramycoides SP3; Coal overburden leachate; Selenite removal; Selenium nanoparticles; Spectroscopic and ultramicroscopic analyses
• ISSN: 0269-7491; 1873-6424
• DOI: 10.1016/j.envpol.2021.117519

A native strain of Bacillus paramycoides isolated from the leachate of coal mine overburden rocks was investigated for its potential to produce selenium nanoparticles (SeNPs) by biogenic reduction of selenite, one of the most toxic forms of selenium. 16S rDNA sequencing was used to identify the bacterial strain (SP3). The SeNPs were characterized using spectroscopic (UV–Vis absorbance, dynamic light scattering, X-ray diffraction, and Raman), surface charge measurement (zeta potential), and ultramicroscopic (FESEM, EDX, FETEM) analyses. SP3 exhibited extremely high selenite tolerance (1000 mM) and reduced 10 mM selenite under 72 h to produce spherical monodisperse SeNPs with an average size of 149.1 ± 29 nm. FTIR analyses indicated exopolysaccharides coating the surface of SeNPs, which imparted a charge of −29.9 mV (zeta potential). The XRD and Raman spectra revealed the SeNPs to be amorphous. Furthermore, biochemical assays and microscopic studies suggest that selenite was reduced by membrane reductases. This study reports, for the first time, the reduction of selenite and biosynthesis of SeNPs by B. paramycoides, a recently discovered bacterium. The results suggest that B. paramycoides SP3 could be exploited for eco-friendly removal of selenite from contaminated sites with the concomitant biosynthesis of SeNPs. [Display omitted] •First report of selenite reduction and SeNPs production by Bacillus paramycoides.•Extremely high selenite tolerance up to 1000 mM.•Efficient removal of selenite was achieved within 72 h.•Selenium nanoparticles exhibited a long shelf life at room temperature.•Potential for use in removal of selenite from industrially polluted environments.