Agrobacterium tumefaciens GV3101 (ATG): an emerging green biosorbent for high-efficiency Hg(ii) capture from contaminated wastewater

Abstract

The growing interest in microbial adsorbents for heavy metal remediation arises from their inherent safety, efficiency, and environmental compatibility. In this study, isolates of Agrobacterium tumefaciens GV3101 (ATG) were selected for their exceptional tolerance to Hg(II). Under optimized in vitro conditions, biosorption assays demonstrated a maximum Hg(II) removal efficiency of 92.70% and an adsorption capacity of up to 322.72 mg g⁻¹. Thermodynamic analyses revealed that the adsorption process was spontaneous and endothermic. Systematic optimization via the response surface methodology based on the Box–Behnken design (RSM-BBD) clarified the influence of key variables on adsorption performance. Mechanistic studies indicated that Hg(II) adsorption critically relies on abundant surface-exposed active sites enriched with functional groups—particularly nitrogen- and sulfur-containing moieties—that facilitate efficient binding and removal from aqueous solution. This work presents a novel Agrobacterium strain as a highly effective biosorbent for mercury, highlighting the potential of diverse microbial resources for sustainable wastewater treatment.