Biochemical and bio-catalytic properties of an enzyme are essential to evaluate its potential industrial applications in food, pharmaceutical, textile, paper and pulp. More specifically, identifying optimal pH and temperature, and their effects on the residual enzyme activity are of high priority in biochemical characterisation. Therefore, in this study, polygalacturonase (PGase) produced as an extracellular enzyme in an earlier study growing Bacillus subtilis on hazelnut shell hydrolysate was evaluated under varying pH and temperature for its stability. The optimal pH and temperature values of the enzyme were found as 7.0, and 50 degrees C, respectively. The enzyme K-m and V-max values were identified as 0.52 mg/mL and 3.27 mu mol/min. The enzyme retained about 93 and 78% of its initial activity at 50 and 60 degrees C after 7 h, respectively. SDS-PAGE revealed a single activity band with molecular weight of 50 kDa. The half-life of PGase at 50 and 60 degrees C were 57.8 and 23 h, respectively. Thus, the results prove the potential of the B. subtilis pectinase produced using hazelnut shells in food processing e.g. extraction and clarification processes or treatment of pectic waste water.