Lanthanides (Ln) are essential ingredients sprinkled in a multitude of applications in our daily life, especially important for sustainable and clean energy applications. However, owing to their chemical similarity, separation of Ln is tedious. In the past decade, the role of Ln for many bacteria has been firmly established, and bacterial strains that take up Ln and use them in the active sites of quinone-dependent alcohol dehydrogenases have been extensively studied. Our studies with the strictly lanthanide-dependent extremophile Methylacidiphilum fumariolicum SolV demonstrate, that the trivalent actinides americium and curium can also support growth in the absence of the essential lanthanides. In fact, the bacteria seem make no distinction between lanthanide and actinide ions if they have the correct size and oxidation state. Time-resolved laser-induced fluorescence spectroscopy, liquid scintillation counting, and inductively coupled plasma mass spectrometry confirm the bacterial uptake of Am and Cm. The interchangeability of f-block elements is supported by very similar enzymatic activities of recombinant methanol dehydrogenase reconstituted with different metal ions. Our combined in vivo and in vitro results establish that actinides support growth of methylotrophic bacteria.From Ln-using bacteria, proteins and small chelators with remarkable selectivity and affinity for lanthanides have been identified. This talk will give a glimpse into possible avenues for lanthanide and actinide separation methods using bacteria or their bioinspired small chelators. We present the extremophilic and strictly Ln-dependent bacterial strain SolV as a platform for the recovery of lanthanides from different sources. SolV can efficiently extract the early Ln such as La and Nd from artificial industrial waste sources, natural Ln-containing and post-mining waters.

Cathleen Zeymer

Appearances