Avaliação da produção de celulases por duas linhagens de leveduras isoladas de frutos de palmeiras

Abstract

The demand for industrial consumption of cellulases has increased due to its use in several sectors of supply. In this sense, the search for alternatives that potentiate the production of cellulases is of paramount importance, given the variety of sources available. The objective of this work was to quantify the cellulases produced by two strains of yeast, besides evaluating the effect of the addition of onosaccharides and disaccharides in the culture means the production of the enzymes and to partially characterize the brute enzymatic extract. Cellulase production was done in culture submerged in five means containing 5 g.L-1 of carboxymethylcellulose (CMC), arabinose, cellobiose, glucose and / or lactose.The tests were conducted at 40 ° C at 150 rpm for 96 hours. In the means with CMC the highest cellulase activity for the T194 lineage was 0.056 U. mL-1 for CMCase, 0.063 U. mL-1 for FPase and 0.096 U. mL-1 for exoglucanase. With the increase of the inducers, the maximum activity values obtained were 0.632 U. mL-1 for CMCase in the means with arabinose, 0.646 U. mL-1 for FPase in the means with arabinose and 0.604 U. mL-1 for exoglucanase, all in the means with arabinose. For the I1236 line in the CMC means the highest cellulase activity was 0.023 U. mL -1 for CMCase, 0.010 U. mL -1 for FPase and 0.003 U. mL -1 for exoglucanase. For the I1236 line in the CMC medium the highest cellulase activity was 0.023 U. mL -1 for CMCase, 0.010 U. mL -1 for FPase and 0.003 U. mL - 1 for exoglucanase. With the addition of inducers, the maximum activity values obtained were 0.619 U. mL-1 for CMCase, 0.514 U. mL-1 for FPase and 0.427 U. mL-1 exoglucanase, all in the medium with arabinose. The partial characterization of the brute enzyme produced by both strains showed significant influence of pH and temperature for FPase and Avicellase and for I1236 only the CMCase activity had no significant difference. The optimum pH range was 5 to 6 for the T194 line and 4 to 6 for the I1236 line and the optimum temperature range was 50 to 58ºC for both lineages for the three enzymes studied. The cellulases produced by the T194 line presented stabilities higher than 70% in the pH range between 7 and 8 and above 80% in the temperature range between 45 and 58ºC. For the cellulases produced by strain I1236 there was stability around 65% for Avicelase and 80% for CMCase and FPase at pH 6 and the thermal stability was higher than 80% between 55 and 65ºC for the three enzymes studied.