Abstract

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 °C, respectively. The enzyme K_m and V_max values were identified as 0.52 mg/mL and 3.27 μmol/min. The enzyme retained about 93 and 78% of its initial activity at 50 and 60 °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 °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.

摘要

酶的生化和生物催化特性对于评估其在食品，制药，纺织，造纸和纸浆中的潜在工业应用至关重要。更具体地说，在生物化学表征中，确定最佳的pH和温度及其对残留酶活性的影响至关重要。因此，在这项研究中，在一个较早的研究中，在榛子壳水解产物上生长枯草芽孢杆菌的情况下，在不同的pH和温度下评估了聚半乳糖醛酸酶（PGase）作为细胞外酶的稳定性。该酶的最佳pH和温度值分别为7.0和50°C。酶K _m和V _max值确定为0.52 mg / mL和3.27μmol/ min。7小时后，该酶分别在50和60°C下保留其初始活性的93％和78％。SDS-PAGE显示分子量为50kDa的单一活性带。PGase在50和60°C下的半衰期分别为57.8和23 h。因此，结果证明了用榛子壳生产的枯草芽孢杆菌果胶酶在食品加工（例如提取和澄清过程或果胶废水处理）中的潜力。