A Yokenella regensburgei strain effectively removes Cu(II), Pb(II), and Cd(II) through a combination of absorption and mineralization modes

Microbial-based heavy metal removal from wastewater is a widely embraced and environmentally friendly method. Nevertheless, its sustainability and efficacy necessitate further improvement. In this study, the strain Yokenella regensburgei GXAS49-I was isolated and characterized for its bioremediation potential. The strain exhibited remarkable resistance to heavy metals, demonstrating a high removal efficiency of 85 % and 90 % for Cu(II) and Pb(II), respectively. The extracellular polymeric substance of GXAS49-I, rich in CO and CO groups, facilitated heavy metal adsorption and played a role in the removal of heavy metal ions. Additionally, GXAS49-I produced hydrogen sulfide, transforming heavy metals into sulfide sediments. Immobilizing GXAS49-I on aerobic granular sludge ensured consistently high removal efficiency for Cu(II) and Pb(II) over four consecutive cycles. The unique dual modes of absorption and mineralization of heavy metals by GXAS49-I, in conjunction with aerobic granular sludge immobilization, position it as an excellent candidate for the sustainable and effective removal of hazardous metals.