“…Biosynthesis methods reduce selenate or selenite to elemental Se by compounds existing in bioorganisms, such as phenols, flavonoids amines, alcohols, proteins, and aldehydes, resulting in specific red SeNPs. [ 14,16,34,79 ] Although, biogenic SeNPs are more frequently produced by prokaryotic cells, [ 14,77 ] such as anaerobic, [ 78 ] aerobic, [ 75,80 ] and anoxic bacteria, [ 14 ] both fungi, [ 81 ] protozoan, [ 82 ] and plant extracts [ 74,83,84 ] have been used as well. The latter is easily manipulated, converting selenate (SeO 4 2− ) into red SeNPs, due to the action of selenate reductases, which first reduce selenate to selenite (SeO 3 2− ), which will be subsequently reduced to elemental Se in the periplasm, by selenite reductases, such as nitrite, nitrate, and sulfite reductase.…”