## 4 Discussion
### In Silico Analysis of Carbohydrate Metabolism of C. leave  
As a result of lignocellulosic destruction, various oligosaccharidesarchides and monosaccharidesrides are released. These are then metabolized by fungi as a carbon source. As for the reactions catalyzed by LPMOs, all these enzymes cleave a polymer chain of cellulose or hemicellulose with oxidation of either the C1 atom (EC 1.14.99.54) or the C4 atom (EC 1.14.99.56) of the glycoside ring to form aldonic acid (or its lactone) or 4-ketoaldose, re  
Figure 8: General scheme of the lignocellulosic degradation enzyme machinery (**A**, **top panel**) and summary of proposed sugar catabolic pathways during lignocellulosic degradation in WRF _Crucibulum__lace_ (**B**, **bottom panel**). Enzymes that are absent from the _C.__lace_ genome are marked in red. The question mark means that the genome of this fungus may contain analogues that are currently unknown. spectively [76]. A fairly large group of LPMOs generate products oxidized both at the C1 and C4 positions in varying proportions. Aldonic acids (or their lactones) are also products of reactions involving AA3_2 and AA7 CAZymes. Thus, the oxidative degradation of lignocellulosic involving enzymes detected in the _C. laeye_ secretomes should produce predominantly oxidized and native oligo- and monosaccharides. The _C. laeye_ genome contains almost all the genes encoding enzymes involved in carbohydrate metabolism through glycolysis, the tricarboxylic acid (TCA) cycle, the glyoxylate cycle, the pentose phosphate pathway (PPP) and the D-galacturonic acid pathway (Figure 8B, Supplementary Table S5). These energy metabolism pathways are highly conserved among different fungi [77]. However, no genes encoding oxaloacetase (OXA, EC 3.7.1.1) were found in the _C. laeye_ genome (Supplementary Table S5). The enzyme hydrolyses oxalcacetate to oxalic acid and acetate in the TCA cycle and the glyoxylate shunt, which uses cytosolic or peroxisomal acetyl-CoA to produce oxaloacetate. Indeed, oxalic acid (oxalate) and acetate were also not detected in CLs of _C. laeye_ (Supplementary Table S5). Oxalate secretion is thought to be a part of the lignocellulosic machinery of both white and brown rots, enhancing the action of lignolytic enzymes such as MnP and LiP in white rots and intensifying the Fenton reaction in both rots [78]. Nevertheless, it has been shown that some fungi (for example, _Trichoderma resei_ and _Planerochate chrysosporium_), such as _C. laeye_, do not contain OXA genes in their genomes [77]. However, the _C. laeye_ genome contains the protein Bicupin (oxalate decarboxylase/oxidase). Two different activities are known for members of this family: oxalate decarboxylase (EC 4.1.1.2) and oxalate oxidase (EC 1.2.3.4). Typically for fungi, oxalate decarboxylase leads to the formation of formic acid and carbon dioxide, and the oxidation of oxalic acid catalyzed by oxalate oxidase leads to the formation of carbon dioxide and hydrogen peroxide [79]. Interestingly, carbonic acid was found among the metabolites, and the peak intensity of this compound increased significantly on the sawdust medium compared to the GP medium (Supplementary Figures S4-S7 and Tables S1-S4). D-galacturonic acid is the main component of pectin and an important carbon source for various microorganisms. Similarly to other fungi, D-galacturonic acid in _C. laeye_ is catabolized via the non-phosphorating pathway (M00630) to glycerol (Figure 8B). Probably, due to the rapid metabolism, galacturonic acid was not detected among the metabolites. In fact, the growth rate of _C. laeye_ on the agar media with pectin was higher than on the media with CM cellulose and xylans (Figure 2). According to the metabolic pathway analysis, _C. laeye_ can catabolize both D-glucose via the glycolytic pathway (glycolysis or Entner-Doudoroff pathway) as well as D-gluconic acid resulting from D-glucono-1,5-lactone hydrolysis (Figure 8B, Supplementary Table S5).