Enzymes production and biomass degradation ability of Malbranchea pulchella cultivated in cellulose pulp and untreated eucalyptus

The challenge in cost reduction of second-generation ethanol production has encouraged several advancements in the platform of biochemical conversion of lignocellulosic materials. Thus, opportunities for creating new enzyme cocktails are focused in strategies such as the identification of new fungi which are potential producers of more active and robust enzymes.  Here, we searched for new enzymes and the degradation ability of the filamentous thermophilic fungus Malbranchea pulchella. The fungus was grown in semi-solid medium at pH 7.0 and 45°C for periods varying from 7 to 21 days. Mass balance of components, image analysis by scanning electron microscopy (SEM) and UV-microspectrophotometry were used to perform a comparative analysis of the degradation process. The enzymes produced in the cultures were analyzed by means of relative activity. The results indicated high xylanase activities. Other enzymes with high relative activity were CMCases in extracts from the culture with cellulosic pulp, and mannanases in extracts from culture with eucalyptus. Additional analyses were performed for the fungus characterization by measuring its mycelium growth rate. Observations of the growth in 16 different substrates indicated that the fungus is a potential CAZyme producer.  Moreover, the confirmation of its thermotolerance with a range of 37 °C – 45 °C for optimum growth, and the prominent tolerance to pH variations (6.0 - 7.5) may reflect in the characteristics of its enzymes stability, which are important to be considered for biorefinery applications.