# Cellulases Production by a _Trichoderma_ sp. Using Food Manufacturing Wastes
## 3 Results and Discussion
found 14 and 12 cellulases, respectively [38]. In a study using _Aspergillus niger_ and _T. reesei_ grown on sugarcane with two levels of cell wall complexity, culm in natura and pretreated, [PERSON] et al. found that although _A. niger_ and _T. reesei_ both produced cellulases, _A. niger_ produced two times more enzymes than _T. reesei_[39]. In general, the activities from the culture supernatants agreed with the mass spectrometry data. Glucose was found repressive as expected; however, five \(\beta\)-glucosidasees were still found in the culture  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**E.C. Number** & **GH Family** & **Predicted Protein** & **Glucose** & **OMSW** & **TP** & **GP** \\ \hline \hline \multicolumn{6}{c}{**Endoglucases**} \\
3.2.1.4 & GH7 & Endo–\(\beta\)-1,4-D-glucanase EG-1 & & x & x \\
2 & & & & & \\  
H3 & Probable \(\beta\)–glucosidase ARB\supernatant of this simple substrate. These results are similar to those of [PERSON] et al. who found that _T. harzinum_ cultured with glucose presented two \(\beta\)-glucosidases [37]. These enzymes might be responsible for the residual activities seen in Figure 4c. Only one endo-\(\beta\)-1,4-D-glucanase was found in our analysis. However, 14 1,4-\(\beta\)-D-glucan cellobiohydrolases were found in the culture supernatants from FMWs samples. The cellulolytic system of _T. reesei_ has been studied in detail. It is composed by seven endo-\(\beta\)-1,4-D-glucanases, two 1,4-\(\beta\)-D-glucan cellobiohydrolases, and seven \(\beta\)-D-glucosidases. The endo-\(\beta\)-1,4-D-glucanases belong to the GH5, GH7, GH12, and GH45 families, and the 1,4-\(\beta\)-D-glucan cellobiohydrolases belong to the GH6 and GH7 families. Finally, the \(\beta\)-glucosidases belongs to the GH3 family [18; 23; 40]. In the cellulose degradation model by enzymes from _T. reesei_, the enzyme endo-\(\beta\)-1,4-D-glucanases acts by cleaving off the amorphous regions of the chain, while the 1,4-\(\beta\)-D-glucan cellobiohydrolases cleave off at the nonreducing and reducing ends. The oligosaccharide products from this hydrolysis are further hydrolyzed into monosaccharides by \(\beta\)-glucosidase into glucose. Other accessory enzymes such as lytic polysaccharide monooxygenases and swollenin, which expands cellulose chains to improve enzyme accessibility, were not found in our four culture conditions [18; 23; 40]. From a biorefinery prospective, enzyme cost is one of the main drivers of the viability of commercial-scale production of bioethanol, representing around 20-40% of the operating costs in a lignocellulosic biomass-based biorefinery [19; 22]. Using low-value substrates to produce enzymes onsite could be an option to make a bio-ethanol facility more sustainable and economical. Currently, most economic studies assume purchasing cellulases from an enzyme manufacturer [19; 41; 42]. Although this approach avoids the capital cost of on-site enzyme production, it includes the transportation of the enzyme to the biorefinery facility, adding a non-trivial amount to the enzyme cost [43]. [PERSON] et al. modeled on-site enzyme generation for ethanol production and found that the carbon source makes up 57% of the cost of enzyme production, followed by 21% capital cost, 13% of electricity, and 9% of other nutrients and fixed costs [44]. Consequently, the utilization of less expensive carbon sources like agroindustrial residues such as OMSW, GP, and TP will allow reducing the cost of enzymes, thereby reducing ethanol production costs. This investigation suggests that _Trichoderma_ sp. can grow on a wide range of carbon sources, including complex substrates such as FMWs. This enables a great variability in the production of cellulases and other enzymes (data not shown), since gene expression and enzyme secretion are directly dependent on the substrate being consumed. Accordingly, in FMWs, whose full chemical composition is still unknown, sugars released during fungal hydrolysis might induce or repress cellulase genes at different levels.