Abstract

Proteases can be used in several biotechnological processes including detergent, food and leather industries. In the leather industry, dehairing is carried out by chemicals, which pollute the environment. Therefore, to make the hair removal process environmentally friendly, a protease produced by Aspergillus terreus has been purified, biochemically characterized and had an efficient ability to remove hair from bovine leather. The protease was produced using 1% wheat bran and was purified 2.3-fold using two chromatographic steps showing a molecular weight of 90 kDa. Optimal temperature and pH were 50 °C and 6.5, respectively. Thermal stability was up to 1 h at 50 °C. Protease was stable to detergents like Tween 80 and to organic solvents. The activity was activated by Ca²⁺ and inhibited by Hg²⁺ and Cu²⁺. The enzyme was classified as serine protease, by the inhibition by PMSF and was stable to reducing agents. It hydrolyzed casein, azocasein, BSA, egg albumin and BTpNA. The Km and Vmax values were 0.65 ± 0.03 mg/mL and 3.66 ± 0.18 μmol/min, respectively. Remarkable properties about temperature, pH, stability to detergents and reducing agents ensure that the protease from A. terreus can be an excellent candidate for industrial applications, particularly in the leather industry.

摘要

蛋白酶可用于多种生物技术过程，包括洗涤剂，食品和皮革工业。在皮革工业中，脱毛是通过化学药品进行的，这些化学药品会污染环境。因此，为了使脱毛过程对环境友好，已纯化，生化表征了由曲霉属曲霉产生的蛋白酶，并具有从牛皮革中脱毛的有效能力。使用1％麦麸生产蛋白酶，并使用显示90 kDa分子量的两个色谱步骤将其纯化2.3倍。最佳温度和pH分别为50°C和6.5。在50°C下的热稳定性高达1 h。蛋白酶对诸如Tween 80之类的去污剂和有机溶剂均稳定。该活性被Ca ²⁺激活并被Hg ²⁺和Cu ²⁺抑制。该酶通过PMSF的抑制作用被分类为丝氨酸蛋白酶，对还原剂稳定。它水解酪蛋白，偶氮酪蛋白，BSA，蛋清蛋白和BTpNA。Km和Vmax值分别为0.65±0.03 mg / mL和3.66±0.18μmol/ min。关于温度，pH，对洗涤剂和还原剂的稳定性的显着特性确保了来自土壤曲霉的蛋白酶可以成为工业应用（特别是皮革工业）的极佳候选者。