Core-shell materials are of enormous interest for many applications in nanotechnology and nanomedicine. Only recently, due to the achievements of the consortium, the generation of such nanoparticles by applying unique proteins from marine organisms has become possible. In this IAPP, based on a long-term and very successful cooperation between groups in Germany and Croatia, well known in the field of marine biotechnology of sponges and associated microorganisms, and now extended by an SME (NanotecMARIN GmbH) with a special focus on the exploitation of marine metal-oxide forming enzymes / proteins, a marine bacterial multicopper oxidase (MCO) and a sponge laccase, which are able to catalyze the oxidation of Mn(II) to Mn(IV), will be used to generate novel metal oxide nanocomposite materials. Enzymatically active MCO will be immobilized on magnetic iron oxide nanoparticles to enzymatically fabricate core-shell materials. In addition, MCO and laccase will be applied in combination with silica or other metal oxide-forming proteins (recombinant silicatein and silintaphin-1) to generate nanoparticles containing multiple shells of various materials, which can be doped with fluorescent dyes and proteins during their formation at mild conditions. These core-shell nanoparticles will be used in drug delivery, for removal of manganese or other heavy metals from contaminated aqueous solutions (remediation of contaminated environments), as well as for the development of antifouling strategies.