Cellulase Activity and Kinetics in Rice Grasshopper Hieroglyphus banian (Orthoptera: acrididae)

Grasshopper (Hieroglyphus banian), an orthopteran species is considered to be a serious pest of rice plant in India. To study the activity and kinetics of cellulase in grasshopper this experiment is undertaken and accordingly foregut and midgut homogenates were prepared. The cellulase enzyme activity and kinetics was measured by DNSA method of Miller,(1959) by taking different concentrations of crystalline cellulose substrate in spectrophotometer at 540nm. Cellulase activity in foregut and midgut were found to be 0.482 u/mg of tissue and 0.687u/mg of tissue respectively. K_m values were determined separately both in foregut and midgut and were found to be 3 mg/dl and 2 mg/dl respectively. Experimental data indicates the presence of high cellulolytic activity in the midgut which may suggest that cellulases of endogenous origin are present in this organism. It can be expected that in future, detailed study of these efficient lignocellulolytic systems will help in identification of novel enzymes possessing features that optimize biotechnological applications for the biofuel industry. Moreover, identification of crucial insect cellulases may help in the development of insecticidal technologies aimed at inhibiting their vital digestive role. Considering that this grasshopper species is a pest of paddy and grass, characterization of insect cellulolytic systems may aid in reducing the grasshopper pest attack in Indian subcontinent.