The potential of wood-rotting and litter-deconstructing basidiomycetes to convert lignocellulose into a wide variety of products has been extensively studied. In particular, wood-rotting basidiomycete secretomes are attracting much attention from researchers and biotechnology companies due to their ability to produce extracellular hydrolytic and oxidative enzymes that effectively degrade cellulose, hemicellulose, and lignin of plant biomass. An analysis of the available literature data shows that Basidiomycota fungi, which are most adapted to the depolymerization of plant polysaccharides, are promising but so far unexploited sources of new hydrolytic enzymes. The review summarizes the latest data on the great variety, common features, and unique properties of individual fungi and the production of cellulases and xylanases by various physiological and ecological groups of basidiomycetes. The most important microbial cellulase-producing strains for submerged and solid-phase fermentation, as well as the main substrates, including the use of agro-industrial waste, are considered. It highlights ways to increase both cellulase and xylanase expression levels and the cost-effectiveness of producing these enzymes for various biotechnological applications. It is anticipated that this review will be particularly useful to novice scientists working in the lignocellulose biorefinery, as it describes current knowledge and issues related to the production and regulation of polysaccharide hydrolyzing enzyme synthesis.

Five white-rot basidiomycetes (WRB) species have been evaluated for their potential to tolerate and to degrade 0.2 mM 2, 4, 6-trinitrotoluene (TNT) as well as to produce laccase and manganese peroxidase (MnP) in presence of this xenobiotic. The tested fungal strains produced laccase in both glycerol and mandarin peels-containing media, whereas in the glycerol-containing medium only Cerrena unicolor strains and Trametes versicolor BCC 775 secreted MnP. Replacement of glycerol by milled mandarin peels 3- to 45-fold increased laccase activity, promoted C. unicolor strains and T. versicolor MnP secretion and induced this enzyme production by Fomes fomentarius BCC 38 and Funalia trogii BCC 146. Differential response of the WRB strains to the TNT addition was observed. In particular, laccase activity of C. unicolor increased 2- to 3-fold in both media whereas no stimulation of the laccase production was revealed in cultivation of F. fomentarius. TNT practically did not affect the MnP activity. Two strains of C. unicolor followed by T. versicolor producing laccase and MnP almost completely removed 0.2 mM TNT from the synthetic medium. Increase of TNT concentration from 0 to 0.4 mM in the mandarin peels-based medium and from 0 to 0.3 mM in the glycerol-containing medium stimulated C. unicolor BCC 300 laccase production from 92.4 to 240.7 U/ml and from 17.1 to 48.6 U/ml, respectively. This strain has been resistant to the TNT high concentration and has ability to remove 85 % of initial 0.3 mM TNT content during 6 days of the submerged cultivation.

In this study, wood-rotting basidiomycetes were screened for cellulase and xylanase production in submerged fermentation of crystalline cellulose and lignocellulosic materials. Phanerochaete chrysosporium ATCC 24725 was selected as the most promising enzyme producer, and the physiological mechanisms controlling the synthesis of cellulase and xylanase were elucidated. The inducible nature of cellulase synthesis and the influence of catabolite repression were characterized. The enzyme preparation isolated after culturing the fungus in a fermenter was partially purified and characterized. The obtained results highlight the potential of P. chrysosporium ATCC 24725 as a reliable fungal cellulase producer for biorefinery applications.

In this study, nine wood-rotting basidiomycete species were screened for cellulase and xylanase production in submerged fermentation of crystalline cellulose. Phanerochaete chrysosporium ATCC 24725 was the best producer of CMCase and xylanase, with enzymatic activity of 71.7 U/mL and 75.9 U/mL, respectively. The total cellulase, endoglucanase, and xylanase activities of P. chrysosporium ATCC24725 in the presence of lignocellulosic substrates were 3–7 times lower than the activity of these enzymes in the medium with crystalline cellulose. However, the endoglucanase activity of Trametes ochracea BCC76 in the medium containing tangerine pomace was the same as in the medium containing Avicel, whereas the xylanase activity was 3 times higher. Cellulase and xylanase synthesis in P. chrysosporium ATCC24725 occurs through induction mechanisms. Cellulose and cellulose-containing materials are the most suitable substrates for cellulase and xylanase production in P. chrysosporium ATCC24725, whereas CMC and xylan proved to be poor substrates for stimulating the secretion of these enzymes. In P. chrysosporium ATCC24725, cellulase and xylanase synthesis do not occur in the presence of easily metabolizable carbon sources due to catabolite repression, even if cellulose is present in the nutrient medium. Induction of enzyme synthesis resumes only after the easily metabolizable carbon source is depleted. The enzyme preparation isolated after culturing the fungus in a fermenter was partially purified and characterized. A crude cellulase preparation from P. chrysosporium ATCC24725 showed similar efficiency as Accellerase 1500 in the hydrolysis of alkali-pretreated wheat straw. The obtained results highlight the potential of P. chrysosporium ATCC 24725 as a reliable fungal cellulase producer for biorefinery applications.