Novel Aspects in the Enzyme-based Transformation of Polyphenols

The biotechnological conversion of lignocellulosic biomass is widely used within the development and refinement of biorefinery processes. Rather than functionalising lignin, however, enzymatic treatments are currently used during the initial pre-treatment of biomass for easing separation of components, or for funnelling purposes during the production of different fuel classes out of initial degradation products. Numerous studies exist that describe the use lignocellulosic enzymes of laccases, peroxidases, cellulases in biorefinery processes. Nonetheless, enzymes can be used also for specifically functionalising polymeric and monomeric phenols. We present here results obtained for the use of lipoxygenase for the valorisation of lignin that are based on detailed mechanistic insights. We used commercially available lipoxygenase (EC 1.13.11.x) for structurally modifying lignins. We further employed commercially available laccase (EC 1.10.3.2) to generate different structural features within oligomeric lignin chains such as to modify them for surface applications by covalently linking functional moieties naturally not present in lignin to the lignins via non-hydrolysable bonding motifs.