A new keratinase producer, Bacillus sp. BK111, isolated from a poultry feather was identified as Bacillus zhangzhouensis, which is the first report for its keratinolytic activity. The keratinase production was optimized, followed by the enzyme purification and characterization using biochemical assays. A 2.34-fold increase was observed in the enzyme production under optimized conditions. The enzyme was characterized as a serine protease with 42 kDa molecular weight, stable in a wide range of temperature and pH with maximum keratinolytic activity at 60 °C and pH 9.5. The enzyme had a wide range of different substrates with the best performance on the feather meal substrate. Metal ions of Ca²⁺, K⁺, Na⁺ and Mn²⁺ enhanced the enzyme activity. The enzyme showed a great deal of stability in the presence of ethanol, methanol, acetone, 2-propanol, dimethyl sulfoxide, Tween-80 and Triton X-100. Dithiothreitol (DTT), as a reducing agent, caused a twofold increase in keratinolytic activity. The half-life of the enzyme at optimum temperature was calculated to be 125 min and the ratio of keratinolytic:caseinolytic for the enzyme was 0.8. Our results showed the remarkable features of the enzyme that make it suitable for biotechnological usages.

中文翻译：

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来自新型角蛋白酶生产者漳州芽孢杆菌的碱性表面活性剂稳定角蛋白酶的生化表征。

一种新的角蛋白酶生产者，芽孢杆菌属。从家禽羽毛中分离出的 BK111 被鉴定为漳州芽孢杆菌，这是其角质分解活性的首次报道。优化角蛋白酶生产，然后使用生化分析进行酶纯化和表征。在优化条件下观察到酶产量增加了 2.34 倍。该酶被表征为分子量为 42 kDa 的丝氨酸蛋白酶，在很宽的温度和 pH 范围内稳定，在 60 °C 和 pH 9.5 时具有最大的角质分解活性。该酶具有广泛的不同底物，对羽毛粉底物的性能最好。Ca ²⁺、K ⁺、Na ⁺和 Mn 的金属离子²⁺增强酶活性。该酶在乙醇、甲醇、丙酮、2-丙醇、二甲亚砜、Tween-80 和 Triton X-100 存在下表现出极大的稳定性。二硫苏糖醇 (DTT) 作为还原剂，可使角质溶解活性增加两倍。酶在最适温度下的半衰期计算为 125 分钟，酶的角蛋白溶解：酪蛋白溶解比为 0.8。我们的结果显示了该酶的显着特征，使其适用于生物技术用途。