Response surface methodology optimization of milk-clotting protease produced by Pleurotus sajor-caju strain CTM 10057 and its technico-economical evaluation

Abstract: The article purpose is to scale-up the bioreactor design for the serine protease from Pleurotus sajor-caju strain CTM 10057 (called SPPS) production to be profitably used in cheese-making production. The SPPS enzyme has been optimized using central composite design (CCD) statistical design analysis. The optimal conditions are: a carbon source of 15 g/L, a nitrogen source of 2 g/L, agitation of 160 rpm at pH = 5.6. This production is scaled-up using submerged fermentation. Under the optimized conditions, protease yield 75,000 U/mL was 6.5 folds higher than those obtained by the use of the initial conditions (11,600 U/mL). The separation was carried out throughout centrifugation followed by a concentration with evaporation, after which this enzyme was tested in the enzymatic milk coagulation process. According to its milk-clotting ability, it could be used in the cheese industry, as well as other food industries. Interestingly, the economic analysis of this planned bioprocess is leased at a positive gain. The estimated SPPS price will be competitive in comparison with commercial enzymes (Mucorpepsine and Presura). So, SPPS enzyme can be used in cheese making and its process is profitable.