Purification and some properties of the mannanases fromThielavia terrestris

Summary Thielavia terrestris NRRL 8126 cell free supernatants contained mannanase and -mannosidase when cultured on a complex media containing locust bean gum. Using acetone precipitation, SP-Sephadex C50 ion exchange chromatography and preparative gel electrophoresis, the crude enzyme was resolved into one -d-mannosidase and four -d-mannanase components. -d-mannosidase had a specific activity of 0.02 (U/mg) onp-nitrophenyl--d-mannopyranoside substrate. Mannanase components M1, M2, M3 and M4 had specific activities of 28.2, 38.7, 52.8 and 4.17 (U/mg) respectively on purified locust bean galactomannan substrate. pH optima for the enzymes were in the range 4.5–5.5. Mannanase component M4 manifested the greatest thermostability, retaining full activity for 3 h at 60°C. Molecular weights determined by SDS-PAGE were 72 000 for -mannosidase and 52 000, 30 000, 55 000 and 89 000 for M1, M2, M3 and M4 respectively. Carbohydrate contents of the enzymes ranged from 6–36%. Preliminary studies indicate that enzyme components hydrolyse the mannan substrate in a synergistic manner.