Improvement of cellulase production in solid state fermentation by Trichoderma reesei C.P.K. 938 using agroindustrial materials.

COLAVOLPE, M. B.; ORTÍZ, G.; GUITART, M. E.; CAVALITTO, S. F.; FERNÁNDEZ LAHORE, H. M.; ALBERTÓ E.

Congreso; VIII Congreso Latinoamericano de Micología.; 2014

Cellulose is a polysaccharide composed by anhydroglucose units linked by β-1, 4 glucosidic bonds. This polymer is degraded to glucose and other small saccharides by synergic action of three enzymes groups: endoglucanases (EG), cellobiohydrolases (CBH) and β-glucosidases (BGL) commonly produced by filamentous fungi, bacteria and yeast. Cellulose hydrolysis is required by different industries, and mainly in bio-ethanol production. The lignocellulosic biomass is low-cost and renewable feedstocks for bioethanol and cellulolytic enzyme production. In second generation bio-ethanol process, lignocellulosic biomass is hydrolysed to fermentable sugars by enzymatic saccharification, producing a higher yield of saccharides without toxic compounds that can inhibit the later fermentation process. However, this treatment represents 43.4% of total cost of the process, and therefore, a reduction in enzyme production cost is required. The aim of our work is the selection of a new Trichoderma strain and posterior optimization of cellulases production in SSF using cheaper agro-industrial substrates. For this purpose, 12 strains were screened in agar plate using carboxymethyl cellulose and acid-swollen cellulose to evaluate EG and CBH activities. The strain C.P.K 938 was selected due to high productivity and balanced activity ratio close to 1:1 (0.58 for CBH and 0.67 for EG), necessary to good saccharification of lignocellulosic biomass. To select a potential substrate, six agroindustrial products were evaluated: wheat bran, cotton husks, alfalfa straw, dandelion, oat straw and Ilex paraguariensis. Among them, wheat bran was the best substrate for cellulases production 5 IU_EGA/gds and 0.8 IU_FPA/gds. The effect of media composition and culture conditions were evaluated using a Plackett-Burman experimental design. The result shown, that initial pH and moisture content were the main parameters affecting cellulase production. Consequently, these variables were optimized using Central Composite Design (CCD). The results show an optimal range for both activities pH: 6.4-6.61 and humidity 74.4%-90%, with activities values 8-10 IU_FPA/gds and 15.6-17.8 IU_EGA/gds. In conclusion, a 12.5 fold increase for FPA and a 3.56 fold for EGA were obtained. These results suggest that C.P.K 938 could be a promising strain for cellulases production and as parental strain in industrial strain development for cellulase production.