Extraction of Crude Enzyme. Extraction of crude enzyme during SSF was accomplished by adding 20 mL sterile distilled water into each conical flask. The flasks were agitated overnight in a rotary shaker at 130 rpm in 25∘C. The solution was filtrated using Whatman filter paper number 1 and then centrifuged at 10,000 g, 4∘C for 15 min. The supernatant was kept at −20∘C for further analysis.