Biosorption of Long Half-life Radionuclide of Strontium Ion (Sr+) by Marine Actinobacterium Nocardiopsis sp. 13H

Microorganisms may have a direct action on the fate of organic/inorganic ions in the environment through biosorption, detoxification or bioaccumulation processes. In the present study, the marine actinobacterial Nocardiopsis sp. 13H strain, isolated from different nuclear power plant (NPP) sites, India, tested for long half-life radionuclide of strontium (Sr⁺) was studied. Nocardiopsis sp. 13H could remove 93.6 ± 0.8% of Sr⁺ from test solutions containing 10 mM SrCl₂. The biosorption of Sr⁺ was studied for optimum condition of pH, temperature and time interval of remediation. Further, Sr⁺ adsorption was confirmed by scanning electron microscopy (SEM) coupled with energy-dispersive spectroscopy (EDS). In addition, with the presence of Sr⁺, extracellular polymeric substances (EPSs) were also found more and suggested interaction of EPS surface active assemblages being involved in radionuclide remediation. Fourier transform infrared (FTIR) study confirmed that Nocardiopsis sp. 13H cell surfaces are involved in Sr⁺ adsorption with the presence of dominant functional groups such as carboxyl, hydroxyl and amide groups. The results conclude that marine actinobacterial Nocardiopsis sp. 13H could be useful for the treatment of long half-life radioisotope pollution as an eco-friendly biosorbent in marine environmental cleanup.