Directed evolution biology in resource technology – From the identification of novel inorganic-binding biomolecules to their provision in future resource recovery and recycling processes

This work focuses on the identification and characterization of inorganic-binding peptidic biomolecules for resource recovery. Manifold biological molecules are used in pharmaceutical and nutrition industries but have so far only limited use in resource technology. Geopolitical tensions, decreasing ore grades combined with increasing demand due to the development of new products and markets result in resource scarcity and the need for new (green) innovative recycling and recovery technologies. Here, we present a novel approach for the design and construction of tailor-made selective target-specific proteinaceous molecules for the creation of innovative bio-based resource recovery applications. Novel peptides with high affinity towards minerals, metals and metalloids such as cobalt, nickel, gallium, arsenic and recently plastics have been identified in our working group using directed evolution phage display technology based on large peptide libraries. Until recently, identification of novel peptides was solely based on ten to hundreds of sequences out of libraries consisting of billions of peptides. As of late, next-generation sequencing (NGS) high throughput analysis of phage display libraries allowed for unprecedented insight into said libraries and accelerated identification of target-specific molecules. Here, we present the NGS-guided phage display-based identification of novel metal- and plastic-binding peptides for surface modification including new findings to the underlying selection process. The characterization of said sequences was successfully achieved in nanomolar ranges with solution- and surface interaction technologies such as isothermal titration calorimetry and quartz crystal microbalance with dissipation monitoring. The here presented results and approaches indicate possibilities for the design and the future provision of innovative bio-based recovery and recycling processes.