Peptones are among the most expensive culture components used in the cultivation of microorganisms. This study was performed to prepare a protein hydrolysate from sheep wool using a locally isolated keratinolytic bacterium Bacillus licheniformis EY2 (GenBank: MN809476), and to investigate the usability of the prepared hydrolysate as a peptone in a microbial medium. The optimum pH, temperature, and incubation time for wool hydrolysis and keratinolytic activity were determined as 7.0, 55 °C, and 6 days, respectively. Optimum concentrations of KH₂PO4, MgSO₄, and NaCl were determined as 1.5, 0.5, and 2 g/L, respectively. After the prepared hydrolysate was partially purified, it was converted to wool peptone (WP). The total protein, ash, carbohydrate, and lipid content of WP was found to be 82.7, 7.2, 0.1, and 0.2 g/100 g, respectively. Fourier transform infrared (FTIR) analysis of WP confirmed the formation of sulfoxide bonds (S=O), which indicated the breaking of disulfide bonds. When compared with commercial tryptone peptone (TP), WP was found to be superior for the cell growth performances of Esherichia coli, Bacillus subtilis, Staphylococcus aureus, Lactobacillus plantarum, Pediococcus pentosaceus, Candia albicans and Aspergillus niger. A protein hydrolysate (including wool protein hydrolysate) prepared via microbial hydrolysis was tested for the first time as a peptone source. The cost of WP is much lower than commercial peptones. At the same time, the method developed offers an environmentally friendly approach for the reduction of the amount of unutilized or waste sheep wool. © 2021 Society of Industrial Chemistry and John Wiley & Sons Ltd.

中文翻译：

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地衣芽孢杆菌 EY2 将废羊毛转化为微生物蛋白胨

蛋白胨是微生物培养中最昂贵的培养成分之一。本研究旨在使用局部分离的地衣芽孢杆菌EY2（基因库：MN809476）从绵羊毛中制备蛋白质水解物，并研究所制备的水解物在微生物培养基中作为蛋白胨的可用性。羊毛水解和角质分解活性的最佳 pH 值、温度和孵育时间分别确定为 7.0、55°C 和 6 天。KH ₂ PO4、MgSO _{4 的}最佳浓度和 NaCl 分别测定为 1.5、0.5 和 2 g/L。将制备的水解物部分纯化后，转化为羊毛蛋白胨（WP）。发现 WP 的总蛋白质、灰分、碳水化合物和脂质含量分别为 82.7、7.2、0.1 和 0.2 g/100 g。WP 的傅里叶变换红外 (FTIR) 分析证实了亚砜键 (S=O) 的形成，这表明二硫键断裂。与商业胰蛋白胨 (TP) 相比，发现 WP 对大肠杆菌、枯草芽孢杆菌、金黄色葡萄球菌、植物乳杆菌、戊糖片球菌、白色念珠菌和黑曲霉。通过微生物水解制备的蛋白质水解物（包括羊毛蛋白质水解物）首次作为蛋白胨来源进行了测试。WP 的成本远低于商业蛋白胨。同时，所开发的方法提供了一种减少未使用或废弃羊毛量的环保方法。© 2021 工业化学学会和 John Wiley & Sons Ltd.