The importance of fermentative conditions for the biotechnological production of lignin modifying enzymes from white-rot fungi

White-rot fungi are the main natural producers of lignin-modifying enzymes, i.e. laccases and peroxidases, whose secretion and activity allows the depolymerization of lignin and the release of polysaccharides contained in lignocellulose. These enzymes are able to oxidize, in addition to lignin, a wide spectrum of natural and synthetic substrates, making their industrial and biotechnological application appealing. However, the complex regulation of the synthesis of lignin-modifying enzymes, as well as the heterogeneous physiology of fungi in response to nutrients, makes the use of white-rot fungi as production platforms challenging. Finally, yet importantly, analytical methods are not fully standardized, making evaluations and comparisons ambiguous. Consequently, robust and cost-effective fermentative processes for the production of lignin-modifying enzymes by fungi have not yet been fully established, limiting their industrial exploitation. In this review, we describe the importance of both the media composition and the fermentative conditions for leveraging the fungal potential in terms of production titer and enzymatic biodiversity of lignin-modifying enzymes.