Browsing by Author "Perrone, Olavo Micali"
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Item Production and biochemical characterization of xylanases synthesized by the thermophilic fungus Rasamsonia emersonii S10 by solid-state cultivation(2021) Zanoni, Jéssica De Araujo; Oliveira, Isabela Brunozi De; Perrone, Olavo Micali; Ortega, Julieth Ordunã; Boscolo, Maurício; Gomes, Eleni; Bonilla Rodriguez, Gustavo OrlandoThe xylanolytic enzyme complex hydrolyzes xylan, and these enzymes have various industrial applications. The goal of this work was to characterize the endoxylanases produced by the thermophilic fungus Rasamsonia emersonii in solid-state cultivation. Tests were carried out to evaluate the effects of pH, temperature, glycerol and phenolic compounds on enzyme activity. Thermal denaturation of one isolated enzyme was evaluated. The crude extract from R. emersonii was applied to breakdown pretreated sugarcane bagasse, by quantifying the release of xylose and glucose. The optimum pH value for the crude enzymatic extract was 5.5, and 80 °C was the optimum temperature. Regarding the stability of the crude extract, the highest values occurred between the pH ranges from 4 to 5.5. Several phenolic compounds were tested, showing an increase in enzymatic activity on the crude extract, except for tannic acid. Zymography displayed four corresponding endoxylanase bands, which were isolated by extraction from a polyacrylamide gel. The thermodynamic parameters of isolated Xylanase C were evaluated, showing a half-life greater than 6 h at 80 °C (optimum temperature), in addition to high melting temperature (93.3 °C) and structural resistance to thermal denaturation. Pretreated sugarcane bagasse breakdown by the crude enzymatic extract from R. emersonii has good hemicellulose conversion to xylose.Item Soaking and ozonolysis pretreatment of sugarcane straw for the production of fermentable sugars(Elsevier B.V., 2019-11-28) Orduña Ortega, Julieth; Mora Vargas, Jorge Andrés; Perrone, Olavo Micali; Metzker, Gustavo; Gomes, Eleni De Barros; Da Silva, Roberto; Boscolo, MaurícioIn the present study, sugarcane straw residue (SCS) is used to generate fermentable sugars. Impregnation in different media and ozonolysis were combined for SCS treatment. The best results were obtained for the basic medium (80 °C at atmospheric pressure for 8 h) followed by ozonolysis (rotary reactor, ozone concentration of 0.24% (w/w), 60 min of reaction and 35% moisture content). Increasing the ozone concentration from 0.24% to 1.3% (w/w) did not increase the amount of glucose released (yields of 60.8 and 60.2%, respectively) indicating that no high ozone concentrations are required. The chemical characterization of the treated material showed that there were no losses due to holocellulose dissolution. In contrast, the cellulose and hemicellulose content increased by 75% and 42%, respectively when compared to the raw material, while the lignin content decreased by 47%. Samples subjected to ozonolysis showed the greatest reduction in the recalcitrance to enzymatic hydrolysis, reaching 60 and 71% of yield in glucose and xylose conversion, respectively, when compared to the impregned material (26 and 31% respectively) and the raw material (4 and 5%).