Chemical Synthesis of Functionalized Peptidomelanin for Groundwater Uranium Extraction

Peptidomelanin is a novel water-soluble fungal copolymer previously identified in Aspergillus niger (strain: melanoliber, MTCC 13366). It is composed of short, heterogeneous peptides covalently linked to a core polymer composed of L-DOPA. Inspired by its unique biochemical composition, this study reports the chemical synthesis of peptidomelanin outside the fungal cell, and without the involvement of any biochemical processes. Cysteine-containing peptides were chemically synthesized and copolymerized with L-DOPA to generate functionalized variants of synthetic peptidomelanin. The resulting copolymers contained polyglutamate to chelate uranium, a major groundwater contaminant and potential resource, with high affinity and selectivity. These findings offer a proof-of-concept for the chemical and biochemical synthesis of functionalized peptidomelanin polymers with tunable metal-binding properties, laying the groundwork for scalable in vivo production of peptidomelanin-based biosorbents for metal extraction and environmental remediation applications.