Enzymatic treatments using laccases offer a more sustainable approach to bleaching lignocellulosic biomass. They reduce the need for harsh chemicals and shorten processing times, which helps preserve the quality of the fibers. Laccases oxidize the phenolic units in lignin via one-electron abstraction, generating reactive radicals. When combined with redox mediators—compounds that form stable radicals—laccases can effectively oxidize non-phenolic lignin structures. At Empa, we are optimizing laccases-based treatments for various types of biomass, such as poplar wood and hemp fibers, by testing different mediators and reaction conditions.