Innovative bioinspired strategies towards selective lanthanide complexation and separation: from bacterial chelators to applications.
Lanthanides (Ln) are critical raw materials and designated with a high supply risk by the European Commission. Their mining and purification have a considerable negative environmental impact and we urgently need sustainable and efficient recycling strategies for these elements. It was recently discovered that many bacteria use Ln for growth and utilize them in the active sites of enzymes. In addition, a Ln-binding protein with unprecedented affinities for Ln (Lanmodulin, LanM) has been isolated from one of these bacteria. The Ln-uptake mechanisms of these bacteria remain vastly underexplored, however, the involvement of polydentate ligands (chelators) to bind lanthanides — lanthanophores (lanthanide carriers) — has recently been established. For the first time, practical applications of chelators that were specifically designed by nature to bind, recycle and separate the technologically-indispensable lanthanides are in reach. Thus, the objective of LANTHANOPHOR is the identification and isolation of lanthanophores from the spent media of lanthanide-utilizing bacteria and the synthesis of short peptides based on the Ln-binding moiety in LanM. A comprehensive characterization of the lanthanophore including their lanthanide coordination chemistry, will contribute to our understanding how Ln are made bioavailable inside bacterial cells. The lanthanophore and the peptides will be evaluated for the use in Ln separation and recycling. I will further elucidate whether these ligands can be used in lanthanide bioremediation or for medical applications as chelators. The results of LANTHANOPHOR will advance the development of sustainable solutions and bioinspired applications that are urgently needed in the quest for new, environmentally friendly and faster Ln separation and recycling technologies. The unique combination of lanthanide biochemistry and coordination chemistry in my group opens unparalleled opportunities for discovery and characterisation of lanthanophores.