Source-Independent Enrichment of Light Lanthanides: Microbial Mobilization, Selective Uptake, and Intracellular Storage.

Poorly soluble lanthanide minerals are a challenge for the sustainable extraction of lanthanides as key resources for the green energy transition and lanthanide-dependent microbial metabolism. Lanthanide-utilising bacteria are widespread in the environment. Their preference for light lanthanides requires differentiation mechanisms that enable downstream utilisation. Whether lanthanide discrimination occurs during access, mobilisation, uptake, or intracellular processing is mostly unknown and likely controlled by habitat and bioavailability. Using Beijerinckiaceae bacterium RH AL1 and combining transcriptomics, analytics, and electron microscopy, we studied microbial lanthanide mobilisation and uptake from different lanthanide minerals, an alloy, and pure lanthanide compounds. Strain AL1 is a facultative methylotroph that depends on light lanthanides for methanol oxidation and known for periplasmic lanthanide accumulation. We could show that strain AL1 grew with all tested lanthanide sources and selectively enriched light lanthanides independent of the source, lanthanide content, and the proportion of light lanthanides. Transcriptomics revealed that the source type significantly influenced gene expression. Lanthanide discrimination in Beijerinckiaceae bacterium RH AL1 is a multilayered process, likely rooted in the complementary action of chelation, uptake, and periplasmic storage. Strains that mobilise lanthanides and increase their bioavailability can transform mineral-bound lanthanides into shared resources for microbial communities, with implications for sustainable lanthanide use.