Inducing effect of salicin for extracellular endoglucanase synthesis in Rhizopus oryzae PR7 MTCC 9642.

The induction of endoglucanase of Rhizopus oryzae PR7 MTCC 9642 has been observed in cultivation medium using a batch-fermentation technique. The effect of various experimental parameters such as use various carbon sources as inducers, concentration of inducer and effect of different additives were investigated. Salicin at concentrations from 0.25 to 0.75% (w/v) was found to bring about a remarkable increase in endoglucanase synthesis when used as a sole carbon source and thought to act as a gratuitous inducer of the enzyme. Endoglucanase activity increased within 24 h after the addition of salicin, reached maximum after 48 h and maintained high level even after 120 h of fungal growth. Repression of enzyme synthesis by glucose could partially be restored by addition of salicin at an early phase of growth. The carboxymethyl cellulose induced enzyme was inhibited by cyclohexamide and ethidium bromide and partially recovered by the salicin which indicated that salicin might act at the transcriptional but not translational level.