Fig. 5.

Degradation of keratinaceous materials in a long-term incubation. a Pig bristle treated for 4 days with culture broth supernatant and with fractions of culture broth. Culture broth on pig bristle: culture broth supernatant from O. corvina grown for 11 days on fermentation medium with pig bristle; culture broth on chichen feathers: culture broth supernatant from O. corvina grown for 11 days on fermentation medium with chicken feathers. b Bristles and hooves (ground into particles approx. 1–2 mm in diameter) treated for 4 days with culture broth supernatant of O. corvina grown on chicken feathers. Negative control: 2× McIlvaine buffer (pH 8). c Pig bristle treated for 24 h with culture broth on chicken feathers and commercial keratinolytic proteases (alcalase, savinase, and esperase). The dosage of enzymes was based on the same protein concentration of the keratinolytic proteases in culture broth and the commercial enzymes. The degree of degradation was calibrated to negative control