Optimization of the drying parameters for an enzymatic extract, and an evaluation of the subsequent proteolytic and cellulolytic activities

Résumé

Enzymes reduce the activation energy needed to convert a substrate into product and are therefore called biological catalysts. Peptidases are enzymes that act on the peptide bonds present in protein substrates, whereas cellulases act in various ways to degrade cellulose. Two types of cellulases are endoglucanase and exoglucanase, called in this paper carboxymethylcellulase (CMCase) and Avicelase, respectively. Trichoderma spp. can produce cellulases and peptidases due to the versatility of their saprophytic characteristics. The drying of enzymes is an interesting procedure because it provides the highest long-term stability. The enzymatic extract produced by Trichoderma harzianum was submitted to spray drying, and the stabilities of the dried enzymes were verified using casein as the substrate for a peptidase assay and carboxymethylcellulose and Avicel as substrates for a cellulolytic activities assay. The aim of this work was to select the adequate adjuvant and to evaluate the best parameters to use in drying the T. harzianum enzymatic extract, which contained peptidase, CMCase and Avicelase. We also wanted to verify the stability of these enzymes after the dried microparticles were solubilized and stored at 4°C or 25°C for 30 days.