The pH stability profiles, reported in Fig. 2b, showed that the crude enzyme extract is highly stable over a wide broad pH range, maintaining more than 90% of its original activity between pH 6.0 and 11.0, and more than 80% at pH 5.0 and pH 12.0 after 1 h incubation at 4◦C. The crude enzyme was highly stable even after incubation for 24 h.