## 4 Discussion
### Secretion of Enzymes Related to Degradation of Lignocellulose
In our study, oligosaccharides oxidase (AA7 family CAZymes, TFK39177.1), whose increased secretion is reported on all the sawdust-containing media, and the GMC oxidoreductase (AA3_2 CAZy family, TFK37403.1), detected on the alder sawdust-containing medium (GP-A), can act as redox partners for LPMOs. In addition, according to another established molecular mechanism, lacase-mediator systems (LMS) release low-molecular weight phenolic compounds from lignocellulosic, which are also electron donors for LPMOs [73]. Lacases were identified in the _C. laeve_ secretomes and their secretion increased on the sawdust-containing media. Interestingly, the initial media with sawdust contained free phenols, whose concentration in CLs decreased significantly at the end of the cultivation (Table 2). On the one hand,phenoxy radicals resulting from lacase-induced phenol oxidation can then polymerize; on the other hand, phenols can be metabolized by the fungus. In _C. laeve_ secretomes, the lytic enzyme repertoire includes glycoside hydrolases (GH16, GH17, GH18, GH31, GH37, GH47, GH51, GH72 CAZy families) and glycoside esterases (CE4 and CE16 CAZy families), most of which are involved in the fungal cell wall remodeling. Interestingly, the CE16 enzyme (universal acetylesterases involved in hemicellulose degradation) was detected on the GP-B medium. A wide range of differentially secreted lectins was found in the _C. laeve_ secretomes (Figure 4). A recent study reported that fungi from different ecological groups have different lectomes, while the greatest diversity of lectin classes is observed in litter decomposers [74]. This suggests an important biological role for these proteins. A protein profile similar to that of _C. laeev_ secretomes was shown for the WRF _Peniophera lycii_ of the order Rusullales when cultured on a medium containing wood sawdust, where hydrolytic enzymes such as cellulases and hemicelllases of the families GH2, GH3, GH5, GH6, GH7, GH10, GH11 and GH28 CAZY typical for WRF of the Polyproales order were absent; and predominantly oxidative enzymes were detected [30]. The spectrum of oxidative enzymes was represented by lacases (AA1), LPMOs (AA9), GMC oxidoreductasees (AA3) and glucooligosaccharide oxidases (AA7). Currently, no information is available on the proteins of the exoproteomes of fungi of the family _Nidulariaceae_ (Agaricales). However, transcriptional analysis of _C. yuthus bulleti_ (_Nidulariaceae_, Agaricales) showed that on wheat bran medium the highly transcribed CAZymes were the GH13 family encoding \(\alpha\)-amylase, GT32 family encoding \(\alpha\)-galactosidasetransferase, CE4 encoding acetyl xylan esterase, AA7 family encoding glucooligosaccharide oxidase, GMC oxidoreductasees (AA3) and the lacase and LPMO isoforms were also highly expressed [22]. Moderate transcription of cellulases (GH5) and hemi-cellulaases (GH3, GH10, GH30 and GH43) and low transcription of PODs genes were also observed. In summary, the proteome analysis of _C. laeev_ indicated that the members of the family _Nidulariaceae_ may use a predominantly oxidative mechanism for lignocellulosic degradation, at least at certain growth stages (Figure 8A). According to the exoproteome profile, _C. laeev_, like some other saprotrophs from Agaricales, cannot be classified as a typical member of the white rot fungi. Proteins found in the _C. laeev_ secretomes can be further exploited to develop new enzymatic cocktails for lignocellulosic processing and possibly extracting biologically active compounds.