Effectively auto-regulated adsorption and recovery of rare earth elements via an engineered E. coli

• Published in: Journal of hazardous materials Vol. 424; no. Pt C; p. 127642
• Main Authors: Xie, Xiaoman, Tan, Xirui, Yu, Yiyan, Li, Yunchong, Wang, Pengbo, Liang, Yuanhao, Yan, Yunjun
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 15.02.2022
• Subjects: Adsorption; aqueous solutions; biosorption; Biosorption and recovery; cell membranes; citrates; desorption; Escherichia coli; Escherichia coli - genetics; Lanthanide-binding tag; Lanthanoid Series Elements; Metals, Rare Earth; Mining; operon; pmrCAB operon; pollution; Rare earth elements; silica; Silica-binding protein; Terbium; wastes; Lanthanide-binding tag; pmrCAB operon; Rare earth elements; Biosorption and recovery; Silica-binding protein
• ISSN: 0304-3894; 1873-3336; 1873-3336
• DOI: 10.1016/j.jhazmat.2021.127642

Conventional mining processes of rare earth elements (REEs) usually produce REEs-rich industrial waterwastes, which leads to a significant waste of REEs resources and causes serious environmental pollution. Biosorption using engineered microorganisms is an attractive technology for the recovery of REEs from aqueous solution. To regulate the REEs’ adsorption and recovery by sensing extraneous REEs, an engineered cascaded induction system, pmrCAB operon containing a lanthanide-binding tag (LBT) for sensing REEs, was incorporated into E. coli in conjunction with a silica-binding protein (Si-tag) and dLBT anchored onto the cell membrane. The sensing and adsorption capacities for Terbium (Tb), a typical study subject of REEs, were enhanced by screening an effective LBT and increasing the dLBT copy number. The adsorption capacity for Tb reached the highest reported value of 41.9 mgg−1 dry cell weight (DCW). After adhering the engineered cells onto the silica column surface through overexpressed Si-tag, a high recovering efficiency (> 90%) of Tb desorption could be obtained with 3 bed volumes of citrate solution. In addition, the engineered cells also possessed fairly good adsorption capacity of other tested REEs. Our findings showed that the recovery of REEs with high efficiency, selectivity and controllability from aqueous solution can be well achieved via specifically bio-engineered strains. [Display omitted] •A novel recovery system for REEs via engineered strain has been developed.•The REEs adsorption and cell immobilization were automatically regulated.•High adsorption capacity and recovery efficiency (>90%) for Tb were achieved.•Pseudo-first order kinetic model could best describe the biosorption kinetics.