Reduction of tellurite in Shinella sp. WSJ-2 and adsorption removal of multiple dyes and metals by biogenic tellurium nanorods

Te(IV) reduction to Te(0) is a detoxification process in bacteria. Elemental Te nanostructures are new materials, however, the functions of them, such as adsorption ability, have not been fully explored. Shinella sp. WSJ-2 is a highly Te(IV)-resistant bacterium with a MIC of 8 mmol/L. It was able to rapidly reduce 0.3 mmol/L Te(IV) to Te nanorods (TeNRs) within 28 h, and its Te(IV) reduction ability was relatively stable after 14 cycles repeatedly. The size of TeNRs ranged from 50 to 120 nm. The surface of TeNRs was mainly enveloped with proteins and lipids. Moreover, the biogenic TeNRs were capable of removing multiple dyes and metals and were effectively recycled with 100 mmol/L NaCl. Adsorption equilibrium isotherms showed that the maximum adsorption amounts were 618.8, 1076.8, 496.3, 179.3, 58.7 and 275.3 mg/g for Methylene Blue, Azure B, Malachite Green, Cd(II), Cu(II) and Pb(II), respectively. In conclusion, this is the first evidence that the genus Shinella is involved in Te(IV) reduction. The strong sorption of cationic dyes and metals onto TeNRs is probably due to the electrostatic interaction. This study showed the potential of Shinella sp. WSJ-2 in the bioremediation of toxic Te(IV) and adsorption removal of multiple dyes and metals by biogenic TeNRs.