Source-independent enrichment of light lanthanides: microbial mobilization, selective uptake, and intracellular storage

Abstract

Poorly soluble lanthanide minerals pose challenges for both a sustainable extraction of lanthanides as key resources for decarbonization and lanthanide-dependent microbial metabolism. Microbial use of lanthanides is widespread, yet bacterias preference for light lanthanides requires differentiation mechanisms that enable downstream utilization. Whether lanthanide discrimination occurs during access, mobilization, uptake, or intracellular processing is mostly unknown and likely controlled by habitat and bioavailability. We studied microbial lanthanide mobilization and uptake from different lanthanide minerals, an alloy, and pure lanthanide compounds. Beijerinckiaceae bacterium RH AL1 served as a model organism for an integrated approach combining transcriptomics, analytics, and electron microscopy. This facultative methylotroph depends on light lanthanides for methanol oxidation and forms periplasmic lanthanide deposits. AL1 grew with all tested lanthanide sources and selectively enriched light lanthanides independent of source type, overall lanthanide content, and the proportion of light lanthanides. Transcriptomics revealed that the type of lanthanide source significantly influenced gene expression beyond lanthanide utilization. Lanthanide discrimination in Beijerinckiaceae bacterium RH AL1 is a multilayered process rooted in the complementary action of chelation, uptake mechanisms, and periplasmic storage. Adaptations that increase lanthanide bioavailability transform mineral-bound lanthanides into shared resources within microbial communities, with implications for sustainable lanthanide use.