Phytopathogenic fungi are known for producing an arsenal of extracellular enzymes whose involvement in the infection mechanism has been suggested. However, these enzymes are largely unknown and their biotechnological potential also remains poorly understood. In this study, the production and thermostability of extracellular enzymes produced by phytopathogenic Botryosphaeriaceae was investigated. Hydrolytic and oxidative activities were detected and quantified at different temperatures. Most strains (70%; 37/53) were able to produce simultaneously cellulases, laccases, xylanases, pectinases, pectin lyases, amylases, lipases, and proteases. Surprisingly for mesophilic filamentous fungi, several enzymes proved to be thermostable: cellulases from Neofusicoccum mediterraneum CAA 001 and from Dothiorella prunicola CBS 124723, lipases from Diplodia pinea (CAA 015 and CBS 109726), and proteases from Melanops tulasnei CBS 116806 were more active at 70 °C than at any of the other temperatures tested. In addition, lipases produced by Diplodia pinea were found to be significantly more active than any other known lipase from Botryosphaeriales. The thermal activity profile and the wide array of activities secreted by these fungi make them optimal producers of biotechnologically relevant enzymes that may be applied in the food and the health industries (proteases), the pulp-and-paper and biofuel industries (cellulases), or even in the detergent industry (lipases, proteases, amylases, and cellulases).
Keywords: cell-wall-degrading enzymes; cellulases; enzymes de dégradation de la paroi cellulaire; enzymes thermostables; lipases; proteases; protéases; thermostable enzymes.