Abstract The demand for keratinolytic proteases has increased in recent years, in view of their applications in the feed, detergent, fertilizer, leather and textile industries. Recently, studies have focussed on exploration of new and inexpensive carbon sources for their production. Among keratin wastes, dog hair presents no utility and is an environmental concern. In this study, we evaluate the feasibility of using white and melanized dog hair (WDH and MDH, respectively) as alternative substrates for protease production by a Fusarium oxysporum strain. The effects of dog hair concentration, cultivation period, and medium pH on alkaline protease production were investigated using a central composite rotary design (CCRD) and response surface methodology (RSM). The optimization process increased protease activity 14.85- and 7.19-fold, using WDH and MDH, respectively. The alkaline proteases produced from WDH and MDH showed distinct biochemical characteristics. To our knowledge, this is the first report on biotechnological use of this problematic, waste residue. Our results open new avenues for conversion of dog hair into other valuable products, especially feed or fertilizer. Graphical Abstract

中文翻译：

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为顽固和有问题的废物增加价值：使用狗毛生产真菌角蛋白水解蛋白酶

摘要 鉴于角蛋白水解蛋白酶在饲料、洗涤剂、肥料、皮革和纺织工业中的应用，近年来对它们的需求有所增加。最近，研究的重点是探索用于生产的新型廉价碳源。在角蛋白废物中，狗毛没有效用，而且是一个环境问题。在本研究中，我们评估了使用白色和黑色化狗毛（分别为 WDH 和 MDH）作为尖孢镰刀菌菌株生产蛋白酶的替代底物的可行性。使用中心复合旋转设计 (CCRD) 和响应面方法 (RSM) 研究了狗毛浓度、培养时间和培养基 pH 值对碱性蛋白酶产生的影响。优化过程将蛋白酶活性提高了 14.85 倍和 7.19 倍，分别使用 WDH 和 MDH。由 WDH 和 MDH 产生的碱性蛋白酶显示出不同的生化特征。据我们所知，这是关于这种有问题的废渣的生物技术应用的第一份报告。我们的结果为将狗毛转化为其他有价值的产品，尤其是饲料或肥料开辟了新的途径。图形概要