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，确定最佳 pH 值和温度及其对残留酶活性的影响在生化表征中具有高度优先性。因此，在本研究中，在不同的 pH 值和温度下评估了早期研究中在榛子壳水解产物上培养枯草芽孢杆菌中作为胞外酶产生的多聚半乳糖醛酸酶 (PGase)的稳定性。发现酶的最佳 pH 值和温度值分别为 7.0 和 50°C。酶 K _m和 V _max值确定为 0.52 mg/mL 和 3.27 μmol/min。该酶在 50°C 和 60°C 下 7 小时后分别保留了其初始活性的 93% 和 78%。SDS-PAGE 显示分子量为 50 kDa 的单一活性条带。PGase 在 50 和 60 °C 下的半衰期分别为 57.8 和 23 小时。因此，结果证明了使用榛子壳生产的枯草芽孢杆菌果胶酶在食品加工中的潜力，例如提取和澄清过程或果胶废水的处理。