Utilization of non-viable cells compared to viable cells of Stenotrophomonas Maltophilia for copper (Cu(ii)) removal from aqueous solutions

Stenotrophomonas maltophilia is an important bacterium in heavy metal bioremediation. Their application is however limited by the increasing reports of their pathogenic potential and resistance to common antibiotics. Therefore, non-viable cells present an interesting alternative as biosorbents. This study was conducted to investigate the potential of S. maltophilia in non-viable cell forms to remove copper (Cu(II)) from aqueous solutions. The total amount of Cu(II) removed by viable cells and adsorped by non-viable cells were compared and analyzed using equilibrium and kinetic models. Results showed that non-viable cells of S. maltophilia have higher efficacy in removing Cu(II) via surface sorption with 23.900 mg g^-1 Cu(II) adsorped compared to only 10.515 mg g^-1 dry biomass of Cu(II) removed by the viable cells. The adsorption mechanisms complied with the Langmuir equilibrium model (R² value of 0.9957) and the pseudo second order kinetic model (R²value of 1.000). Thus the adsorption was attributed to the functional groups on the cell wall via the monolayer adsorption capacity. Our study showed that non-viable cells of S. maltophilia can be applied and used more effectively than viable cell forms to remove Cu(II) from aqueous solutions.