Enzymatic and chemical modifications of oligoenes and polyenes

Abstract

The thesis addresses the poor water solubility of synthetic polyisoprene (PI), which critically limits its enzymatic degradation. Two emulsification methods—using a co-solvent and acoustical emulsification—were developed to create surfactant-free PI emulsions in aqueous media. Enzymatic degradation with rubber oxygenase LcpK30 showed that bioinspired emulsification significantly increased the integrated degradation fragment area compared to non-emulsified PI. Protein-engineered variants of LcpK30, especially LcpK30-P7 developed via PROSS, exhibited improved thermostability and sustained activity at 60°C for latex milk. A novel rubber oxygenase degradation assay based on GPC-UV was established for tracking enzymatic activity, even at low levels, through quantitative end-group derivatization. Finally, the incorporation of cyclopropanating functionalities via transesterification with bis-NHC-Cu and an auxiliary cross-linker, yielding single chain nanoparticles, was investigated.