Tannery hair wastes are becoming a challenge for tanners regarding environmental pollution control and human health. In this study, an experiment had been designed to hydrolyse sheep hair in an alkaline medium, and the operational condition for the alkaline extraction of KH has been modeled and optimized. The structure, morphology, functional groups, particle size, and molecular mass of the KH extracts were evaluated experimentally by scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy (FTIR), particle size analysis, and SDS-PAGE analysis, respectively. FTIR analysis of the extract confirmed the presence of carboxylic, amide, and aldehyde functional groups and alkyl side chains of amino acids. The molecular weight of the extracted keratin ranges between 3–15 kDa, and X-ray diffraction (XRD) analysis showed an amorphous form of structure with two peaks at 2 theta of 9.36° and 21.16° due to -helix and - sheet structure in keratin. Response surface methodology (RSM) coupled with BOX-Behnken design was applied as a statistical tool to investigate the effect of extraction time, the concentration of the hydrolysing agent, and temperature on the response variable (yield of keratin protein). The concentration of the hydrolysing agent was found to be the most significant factor affecting the speed of extraction, but its gradual increase tends to affect the protein content of the extract. Optimum parameters of 0.5 N, 80°C, and 3.5 hr were obtained for the concentration of NaOH, temperature, and extraction time, respectively, with a maximum average protein yield of 91.5% and a percentage total nitrogen content of 14.6% using the Kjeldahl method and 86.57% using the biuret test method.

中文翻译：

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从制革羊毛废弃物中提取角蛋白水解物的工艺优化

制革厂的毛发废弃物正成为制革厂在环境污染控制和人类健康方面面临的挑战。在这项研究中，设计了一个在碱性介质中水解绵羊毛发的实验，并模拟和优化了 KH 碱性提取的操作条件。通过扫描电子显微镜、X 射线衍射、傅里叶变换红外光谱 (FTIR)、粒度分析和 SDS-PAGE 分析分别对 KH 提取物的结构、形态、官能团、粒径和分子量进行了实验评估. 提取物的 FTIR 分析证实了氨基酸的羧基、酰胺和醛官能团和烷基侧链的存在。提取的角蛋白的分子量范围在 3–15 kDa 之间，-角蛋白中的螺旋和-片状结构。将响应曲面法 (RSM) 与 BOX-Behnken 设计相结合作为一种统计工具来研究提取时间、水解剂浓度和温度对响应变量（角蛋白产量）的影响。水解剂的浓度被发现是影响提取速度的最重要因素，但其逐渐增加往往会影响提取物的蛋白质含量。NaOH 浓度、温度和提取时间的最佳参数分别为 0.5 N、80°C 和 3.5 小时，使用凯氏定氮法获得的最大平均蛋白质产量为 91.5%，总氮含量百分比为 14.6%方法和 86.57% 使用双缩脲测试方法。