Physiological regulation of laccase and manganese peroxidase production by white-rot Basidiomycetes

This review integrates recent literature and our own data on the physiology of laccase and manganese peroxidase synthesis, focusing on the common characteristics and unique properties of individual fungi as well as on several approaches providing enhanced enzyme secretion. Firstly, the enzyme yield is species-dependent and strain-dependent and selection of new organisms with tremendous synthesis of these enzymes is possible. For example, in screening program the laccase activity of tested basidiomycetes varied from 0.5 U ml−1 to 75 U ml−1. Secondly, the carbon source and lignocellulosic substrate play a crucial role in enzyme production. Thus, laccase activity of Pseudotrametes gibbosa varied from 0.3 U ml−1 (Avicel) to 13.7 U ml−1 (lactose), while the substitution of wheat bran with walnut pericarp increased Cerrena unicolor manganese peroxidase yield from 0.7 U ml−1 to 8.3 U ml−1. Thirdly, aromatic compounds regulate the ligninolytic enzyme synthesis although their effect is very specific depending on fungi physiological peculiarities. 2,4,6-trinitrotoluene (TNT) supplemented to the medium at appropriate concentration significantly accelerated C. unicolor laccase production and 4-fold increased laccase specific activity. Fourthly, co-cultivation of appropriate fungi shows considerable promise as a strategy to highly enhance the enzyme production. For example, pairing of C. unicolor and Phellinus robustus 2-fold increased the total laccase yield.