PRODUCTION OF BETA-GALACTOSIDASE FROM THERMOPHILIC FUNGUS RHIZOMUCOR SP

A thermostable beta-galactosidase was produced extracellularly by a th ermophilic Rhizomucor sp, with maximum enzyme activity (0.21 U mg(-1)) after 4 days under submerged fermentation condition (SmF), Solid stat e fermentation (SSF) resulted in a nine-fold increase in enzyme activi ty (2.04 U mg(-1)). The temperature range for production of the enzyme was 38-55 degrees C with maximum activity at 45 degrees C. The optimu m pH and temperature for the partially purified enzyme was 4.5 and 60 degrees C, respectively. The enzyme retained its original activity on incubation at 60 degrees C up to 1 h, Divalent cations like Co2+, Mn2, Fe2+ and Zn2+ had strong inhibitory effects on the enzyme activity, The K-m and V-max for p-nitrophenyl-beta-D-galactopyranoside and o-nit rophenyl-beta-D-galactopyranoside were 0.39 mM, 0.785 mM and 232.1 mmo l min(-1) mg(-1) respectively, The K-m and V-max for the natural subst rate lactose were 66.66 mu M and 0.20 mu mol min(-1) mg(-1).