Optimization of Protease and Amylase Production by Rhizopus oryzae Cultivated on Bread Waste Using Solid-State Fermentation

This research was carried for the coproduction of two industrial enzymes: α -amylase and protease via SSF by Rhizopus oryzae on humidified bread waste. Fermentation time, inoculum size, initial moisture content, salt solutions, and the thickness of the substrate were investigated one by one. Fungus culture was carried out in sterile aluminum trays, and pH was adjusted to 5.5. The main results showed that the highest levels of enzyme production were obtained at 120 h, 65% relative humidity, height media of 1 cm, 10 5 spore/g, and M-9 solution (g/L): NaH 2 PO 4 , 12.8; KH 2 PO 4 , 3; NaCl, 0.5; NH 4 Cl, 1; MgSO 4 7H 2 O, 0.5; CaCl 2 2H 2 O, 0.01. α -Amylase (100 U/g) and protease (2400 U/g) produced by SSF from Rhizopus oryzae (CH4) on BW as substrate are of great interest in industries and could be valorized as enhancers of the bread making process.