Methods of sequestering target elements

A method of sequestering a target element from a sample,

• the method comprising:
• contacting the sample and a lanmodulin protein (LanM protein) in a first solution such that the target element (TE) binds to the LanM protein to form TE-LanM, wherein the first solution is aqueous and has a pH of 2.5 to 6.5, the target element is selected from a rare-earth element (REE), Bi, Tl, and In,
• wherein the LanM protein comprises at least one LanM unit, wherein the at least one LanM unit is a portion of the LanM protein comprising at least two EF hand motifs,
• wherein at least one of the EF hand motifs is of the form SEQ ID NO:
• 2 and at least two of the EF hand motifs of the LanM protein are separated by a space of 10-15 residues,
• wherein the LanM protein is selected from:
• a) wild-type lanmodulin comprising the sequence of SEQ ID NO:
• 1,
• b) homologs of wild-type lanmodulin comprising the at least one LanM unit, and
• c) a protein having portions comprising the at least at one LanM unit;
• recovering the TE-LanM from the first solution by separating the TE-LanM from the sample and LanM protein to form a second solution comprising the TE-LanM;
• adjusting the pH of the second solution to less than 2.5, wherein at the pH less than 2.5, the TE desorbs from the LanM protein;
• separating the LanM protein and the TE;
• and
• repeating the contacting, recovering, and adjusting steps with a second sample and the LanM protein at least once.