Abstract:

Cellulase extract preparation from intestine tract of the longicorn borer (Apriona germari Hope) were tested to determine the cellulolytic abilities. It was revealed that the borers had cellulolytic enzyme complex: exo-β-1, 4-glucanase (C_x-ase), endo-β-1, 4-glucanase (C_x-ase)and β-1, 4-glucosidase in their gut. After comparison of the kinetic properties among cellulases of A. germari, it was showed that the C_x-ase had wider range of adaptability than β-glucosidase. For C_x-ase, the optimun pH was at pH4. 4, whereas β-glucosidase had an optimun pH of 5. 6; C_x-ase had a fairly wide optimun temperature range between 30℃-45℃, but β-glucosidase had a range between 45℃-50℃. Treated with salts of different concentrations and under the same assay condition to test the activity of C_x-ase and β-glucosidase, inactivating effect was observed with Ca⁺⁺, Mg⁺⁺, Co⁺⁺, Cu⁺⁺, Zn⁺⁺, Mn⁺⁺, Ag⁺⁺, Hg⁺⁺ and Pb⁺⁺ under high concentrations (0. 1mol/L). While under low concentrations (0. 005mol/L), the effects showed very slight with Ca⁺⁺, Mg⁺⁺ and Co⁺⁺, but very strong with Hg⁺⁺ and Pb⁺⁺. It is very interesting to note that the Mn⁺⁺ and Cu⁺⁺ are important trace elements for plant growth and also common fungicides and sterilizing agents, they were also proved to be strong cellulase activity inhibitors. It would be possible to develop new devices in control of cerambycid borers.

Key words: Cellulases, Apriona germari Hope, Kinetic properties