Production and some characteristics of beta-glucosidase in Diaporthe (Phomopsis) helianthi.

Diaporthe (Phomopsis) helianthi Munt.-Cvet. et al. is an important phytopathogenic fungus which causes stem canker of sunflower. When grown in submerged cultures in the presence of milled wheat chaff as a carbon source this phytopathogen produced extracellular and intracellular beta-glucosidases. The optimum pH of these enzymes was 4.8. The temperature of crude intracellular beta-glucosidase activity was at 60 degrees C, whereas the optimum activity of crude extracellular beta-glucosidase was observed in a wide range of temperature between 40 and 70 degrees C. Although, extracellular and intracellular beta-glucosidase activities had identical pH and similar temperature optima, the thermal stability of the intracellular enzyme was significantly higher.