Influência do magnésio e da arabinose na produção de celulases por Yarrowia divulgata

Abstract

he current demand for renewable energy sources leads the search for new alternatives for energy production. In this way, the celullases production for lignocellulosic biomass conversion is very important. The aim of this study was to evaluate the magnesium and arabinose influence in the cellulases production b Yarrowia divulgata using a Central Composite Rotational Design (CCRD). The cellulase production was carried out in submerged conditions in a medium with 5g/L of carboximetilcellulose, 20 g/L of NaNO3, 1 g/L of K2HPO4, 0,5 g/L of KCl e 0,2 g/L of peptone, and variable concentration of MgSO4 and arabinose, incubated at 30°C and 150 rpm for 24 hours. It was evaluated the endoglucanase (CMCase), total cellulase (FPase), exoglucanase (Avicelase) and β glucosidase activities. The cellulases activities ranged from 0 to 1.67 U/mL to endoglucanase, 0 to 2.22 U/mL to total cellulase, 0 to 1.45 U/mL to exoglucanase and 0 to 11.67 U/mL to β glicosidase. The analysis of variance (ANOVA) showed that only the MgSO4 was a significant parameter to exoglucanase and β-glucosidase production with 5% of significance. Based on these results, it was performed 7 assays using 3 g/L of MgSO4 without arabinose. In these assays no activity was observed for any of the enzymes. It was observed that the yeast did not reproduce as expected, since the cell counts were below those observed in the media containing arabinose, showing that, probably, the absence of arabinose somehow inhibited cell multiplication and consequently no cellulase production was observed.