The many faces of chitosan : derivatization to improve antimicrobial and metal removal properties

Global warming, fossil fuel depletion and an increasing world population form the basis of many research topics that prioritize a sustainable future for planet Earth and its inhabitants. The reduction and valorization of waste streams creates challenging opportunities for the adjustment of existing industrial processes together with the development of new technologies and products. In this context, chitosan has been thoroughly studied, since it is sourced from waste streams and applied as a building block for added value materials. Chitosan is a polymer of biological origin and is mainly obtained from chitin, which can be found as a structural component in the exoskeleton of crustaceans or insects, or in the cell wall of yeasts and fungi. The unique chemical and biological properties of chitosan, e.g. antimicrobial activity, sorption capacity, biocompatibility, biodegradability, are valued in many fields. However, chemical modification is often necessary to create or increase the desired properties. In this research project, chitosan was chemically modified to obtain multiple derivatives that were tested for three distinct applications. The antifungal, antifouling and metal adsorbing properties were evaluated. Additionally, a novel depolymerization method was established, which allowed to synthesize chitooligosaccharides. The variety of application fields demonstrate the future potential of this compound