Schieder, AndreasAndreasSchiederDiener, JuliaJuliaDienerDiekmann, MartinMartinDiekmannBartsch, ChristianChristianBartschDietrich, FlorianFlorianDietrichFalcke, ClaudiaClaudiaFalckeAnic, IvaIvaAnicRoth, SteffenSteffenRothSieber, VolkerVolkerSieberRichter, MichaelMichaelRichterTaden, AndreasAndreasTaden2023-12-192023-12-192024https://publica.fraunhofer.de/handle/publica/45817810.1039/d3su00269aDefined peptides with exclusive molecular functionalities from biomass streams provide an untapped treasure for innovative biogenic specialty chemicals and materials. In this context, feather keratin, a natural structural protein with high L-cysteine content, enables access to polythiol-containing peptides, which can be used as matrix compounds for new materials per se and be specifically modified via their amino and acid moieties. This study describes an innovative two-step approach for tailored feather keratin fragmentation involving selective enzymatic hydrolysis followed by optional chemical reduction. Several proteases were investigated to serve as a benchmark for the decomposition of chicken feather keratin, and we succeeded in the controlled decomposition of chicken feathers using trypsin and other specific proteases, producing polythiol-containing peptide fragments. We were able to implement a green hydrolysis process without the need for any denaturants or reducing agents and achieved yields of soluble protein up to 81% (w/w) and thiol concentrations up to 21 mmol L-1. The obtained hydrolysates were used to produce peptide films, and the scalability of the newly developed hydrolysis process has been demonstrated in 25 L batch reactions.enjournal article