## 3 Results and Discussion
### Solid-State Production of A. olivimuriae Extracellular Glycosyl Hydrolases and Lyaases  
As expected from the composition changes in the colonized materials and the CAZy prediction, we detected both glycosyl-hydrolase and lyase activities involved in the depolymerization of plant cell-wall polysaccharides in _A. olivimuriae_ solid-state cultures. However, CAZyme production levels varied depending on the residue used and the presence or absence of the amendment. Regarding cellulolytic enzymes, non-amended and amended cultures on RTB yielded the highest endo-\(\beta\)-1,4-glucanase activities (4.11 \(\pm\) 0.81 and 4.40 \(\pm\) 0.69 IU g\({}^{-1}\) substrate, respectively) (Figure 1A). The presence of WB significantly increased this activity compared to homologous non-amended ones, but only in cultures on barley straw (4.40 \(\pm\) 0.58 vs. 3.20 \(\pm\) 0.59 IU g\({}^{-1}\) substrate, respectively). Amended and non-amended cultures on RTB exhibited the highest cellobiohydrolase activity, and the presence of WB resulted in a significant increase in this activity, but only for SCG cultures (2.51 \(\pm\) 0.42 vs. 1.51 \(\pm\) 0.28 IU g\({}^{-1}\) substrate) (Figure 1B). As was already observed for endo-\(\beta\)-1,4-glucanase and cellobiohydrolase, among non-amended cultures, those on RTB gave the highest \(\beta\)-glucosidase activity and, in this case, the presence of WB led to a doubling of production levels (2.68 \(\pm\) 0.38 vs. 1.33 \(\pm\) 0.15 IU g\({}^{-1}\) substrate) (Figure 1C). The total cellulolytic activity was also determined using Whatman filter paper n. 1, a substrate with the merit of the inclusion of amorphous and para-crystalline regions, whose use was proposed by [PERSON] [28] and, later on, recommended by the IUPAC. For this reason, the activity of many commercial cellulolytic preparations is expressed in terms of Filter Paper Units [59]. Figure 1D shows that solid-state cultures on RTB and barley straw yielded the best activity values. The effect of WB was statistically significant in cultures carried out on RTB (2.27 \(\pm\) 0.40 vs. 1.48 \(\pm\) 0.34 FPU g\({}^{-1}\) substrate), barley straw (1.95 \(\pm\) 0.26 vs. 2.98 \(\pm\) 0.60 FPU g\({}^{-1}\) substrate) and in those on DSF (0.97 \(\pm\) 0.12 vs. 0.47 \(\pm\) 0.03 FPU g\({}^{-1}\) substrate) (Figure 1D). Notably, CMCase, FPU and \(\beta\)-glucosidaseide production levels by _Aspergillus coespitosus_ NRRL 1929 and _A. tubingensis_ NRRL 4700 solid-state cultures on RTB were very similar to those observed with the strain under study on the same substrate [60]. DSF was poorly conducive to cellulase production in line with [PERSON] results [51]; in that study, in the solid-state cultures of _T. reseei_ ATCC 26921, a well-known cellulase-producing strain, the enzymatic activity never exceeded 1.1 FPU g\({}^{-1}\) digestate. However, _Aspergillus olivimuriae_ 6C2 cellulase production levels do not compare with hyper-producing strains belonging to the same genus. To exemplify, _Aspergillus terreus_ M11 solid-state cultures on different substrates, such as rape straw, wheat straw, wheat bran and corn stover, reached enzymatic CMCase and FPU activity levels ranging from 122 to 440 IU g\({}^{-1}\) and 12 to 198 IU g\({}^{-1}\), respectively [61]. CMCase, \(\beta\)-glucosidase and FPU activities in _A. fumigatus_ ABK9 grown on WB-rice straw mixed substrate led to 824.21 and 254.44 and 106.2 IU g\({}^{-1}\), respectively [62]. Concerning hemicellulases, this study determined the activities of enzymes involved in the hydrolysis of two ubiquitous hemicellulose components, namely xylan and galactomannan. In addition to the endo-\(\beta\)-1,4-xylanase and galactomaninase activities, which hydrolyze the \(\beta\)(1 \(\rightarrow\) 4) glycosidic bonds between adjacent residues within the chain and in a random manner, we determined the activities of two exo-enzymes acting on these two polymers, namely \(\beta\)-xylosidase and \(\beta\)-manosidase.