Development of Cobalt- and Nickel-binding peptides for biosorption

Usage of Phage Display for identification of peptide binding motifs has long been restricted to medical use. However, in the last years more and more publications focused on the interaction between peptides and inorganic material. Especially in Geobiotechnology the characterization of new metal-binding proteins as well as peptide motifs receives increasing attention, as they may be used in metal recovery, biosorption and bioremediation, as well. Here, we describe the application of artificial peptides for the recovery of metal ions form solutions, e.g. leachates. Limitations arise from complicated identification of metal-binding peptides, from high productions costs of chemical synthesized peptides and difficult heterologous expression of small peptides, as they are relatively fast proteolyzed. Therefore applications of such peptides require efficient and economic production systems. In the present study we aimed for the development of an efficient expression system, expressing previously via Phage Display and Deep sequencing identified peptides as fusions proteins with integrated purification and cleavage tags. Characterization of the purified peptides was performed using quartz crystal microbalance with dissipation monitoring using special coatings for metal immobilization. Knowledge about peptide motifs and metal affinity is crucial for the intended usage of peptides in biosorption processes, e.g. immobilized on membranes. Furthermore, detailed information about peptide-metal interaction may lead to discovery of novel metal-incorporating and –binding enzymes.