Laccase-based synthesis of SIC-RED: A new dyeing product for protein gel staining

In the last years, laccases have become leading biocatalysts in green bioprocesses for dye synthesis. Among fungal laccases, the high-redox potential laccase POXA1b from Pleurotus ostreatus is a valuable candidate since it brings together several key-elements: stability and activity in a wide range of pHs and temperatures and the availability of a cost-effective bioprocess for its production. In this work POXA1b catalyzed the coupling of a p-phenylenediamine and α-naphtol, resulting in the production of a new dyeing product, named SIC-RED. The dye was structurally characterized and its performances in protein gel staining tested. The economic feasibility of the process was demonstrated in the case of an Italian small medium enterprise. The results let envisage a real exploitation of the herein enzymatically synthesized dye for protein gel staining.