As far as protease thermostability is concerned, long-termresidual activity tests were carried out in the temperature range55–70◦C using higher E0(50 U/mL) to speed up the reaction, whose results in terms of the residual activity coefficient ( ) are illus-trated in Fig. 4. Protease activity followed the classical decay of the first-order denaturation pattern already observed for other fungi belonging to the Aspergillus genus