Selection and production of siderophores suitable germanium-, indium and gallium - recovery

Siderophores are a diverse group of small iron-chelating molecules that are synthesized by a vast number of bacteria, fungi and graminaceous plants in order to sequester the essential metal under iron-limited conditions. Their capability to complex other metals as well makes them possibly suited compounds for the usage in bio-based recycling technologies.
The aim of this work is to find siderophores, which selectively bind the critical elements indium, gallium and germanium. Due to the vast number of different known siderophores the complete experimental evaluation is impractical, though. Hence, density functional theory (DFT) is used to simulate the chelation reaction in order to estimate the affinities of various siderophores towards gallium and indium as well as the stability of the resulting coordination complexes. Additionally, environmental samples from lagoons of the Atacama Desert are screened for novel siderophore-producing organisms. The siderophores excreted by those organisms might possess unique binding abilities due to the highly saline and alkaline conditions of the isolation sites. Siderophores selected via DFT as well as those produced by isolated microorganisms are tested experimentally for their affinity towards the metals of interest.
Proving the applicability of siderophores in the recovery of indium and gallium from low concentrated waste waters would create a vast amount of further possible applications of the biomolecules to aid securing the future supply of not just said energy-critical elements, but all strategic metals.