LAUSR

AIMS Heavy metal pollution is a serious and difficult environmental problem. With increasing heavy metal content in industrial wastewater, an environmentally friendly and efficient treatment method must be identified. METHODS AND RESULTS Considering the ability of endophytic bacteria to adsorb metal ions, this paper explored the heavy metal resistance, adsorption, and adsorption mechanisms and performance of S. succinus H3, an endophytic bacterium. S. succinus H3 exhibited metal resistance at 4 mM Cu2+ and 5 mM Mg2+. The adsorption rate of Cu2+ and Mg2+ ions by the live/dead strain was approximately 70%, and the adsorption capacity was positively correlated with the metal ion concentration. The kinetics and isothermal models were used to study the process of S. succinus H3 adsorption on Cu2+. It exhibits a good correlation with the Freundlich isothermal model. The N-H group, protein C=O group, polysaccharide C-O group, O-H group and some lipids are the main functional groups in the cell wall. S. succinus H3 may bond with the amine group to adsorb Mg2+ through complexation/coordination and may form a copper complex after adsorbing Cu2+. S. succinus H3 has a live adsorption rate of 15% in eight mixed metal ion systems at a 50 mg/L concentration. The study results can lay a foundation for expanding the bacterial resource pool of pollutant treatment and improving the efficiency for sewage treatment. The high heavy metal adsorption capacity of microorganisms has a decisive role in industrial wastewater treatment by microorganisms. Such microorganisms with high metal resistance and adsorption capacity to heavy metals can thrive in industrial wastewater, remove heavy metals efficiently, and greatly improve the efficiency of wastewater treatment. CONCLUSION The study results can lay a theoretical foundation for the use of S. succinus H3 to biologically treat heavy metal wastewater in the future.