Rare Earth Element‐Based Recovery Concept for Cofactors Containing Phosphate Groups from Aqueous Solutions

Cofactors, which are key components in many bio‐based processes, are often consumed within the biosynthetic reaction, but are usually converted back to their original form by recycling. This study presents an approach for the selective removal of cofactors from aqueous solution at up to submillimolar concentrations. The rare earth elements (REE) scandium, yttrium, and lanthanum, in the oxidation state +3, are used to form sparingly soluble salts with the investigated cofactors, pyridoxal‐5‐phosphate, NAD+, NADP+, adenosine triphosphate, and thiamine pyrophosphate. Up to > 99 % removal efficiency via cofactor salt precipitation was observed. Redissolution and recovery of the formed salt is obtained via treatment with NaH2PO4 in a salt metathesis reaction, forming the solubilized cofactors with up to > 99 % recovery and the corresponding REE phosphate salts. Cofactors enabling essential steps within biocatalytic cycles are often highly expensive. The rare earth elements, scandium, yttrium, and lanthanum, in the oxidation state +3, can be used to form sparingly soluble salts with phosphate group‐containing cofactors, achieving > 99 % recovery via cofactor salt precipitation.