Yang Shuang, Wang Min, Meng Jingda, Cheng Zhangyuan, Liu Boyu, Xia Jiujie, Gao Wenqi, Shen Yan, Xia Tian, Yu Xin, Guo Chengchen
Research Center for Industries of the Future, Westlake University, Hangzhou Zhejiang 310030, China; Department of Materials Science and Engineering, School of Engineering, Westlake University, Hangzhou, Zhejiang 310030, China.
Research Center for Industries of the Future, Westlake University, Hangzhou Zhejiang 310030, China; Department of Materials Science and Engineering, School of Engineering, Westlake University, Hangzhou, Zhejiang 310030, China.
Bioresour Technol. 2025 Dec;437:133178. doi: 10.1016/j.biortech.2025.133178. Epub 2025 Aug 19.
Keratin, a naturally occurring polymer material, is primarily derived from protein-based biomass such as hair, wool, and feathers. The development of sustainable dissolution technologies is critical for achieving the high-value applications of keratin-rich biomass. This study reports a reductive natural deep eutectic solvent (NADES) system composed of citric acid (CA) and l-Cysteine (l-Cys) for efficiently extracting keratin from wool. Molecular dynamics (MD) simulations revealed key interactions between the solvent components, while experimental evaluations assessed wool dissolution efficiency, keratin yield, and the properties of regenerated keratin. Notably, a 2:1 M ratio of CA to l-Cys enabled complete wool dissolution at 90 °C within 3 h, yielding ∼76 % keratin, comprising 58 % water-insoluble keratin (WIK) and 18 % water-soluble keratin (WSK). SDS-PAGE analysis showed a broad molecular weight distribution for WIK, whereas WSK was primarily below 20 kDa. In situ experiments showed that the optimal solvent system can completely destroy the wool structure at around 1.5 h. X-ray diffraction (XRD) results confirmed a pronounced reduction in the α-helix content of WSK relative to natural wool and WIK. Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and elemental analysis indicated trace CA and l-Cys residues in WSK, which nonetheless exhibited good cytocompatibility. These findings demonstrate a simple, green, and efficient approach for extracting keratin from wool, providing a viable pathway for upcycling keratin-rich waste biomass.
角蛋白是一种天然存在的聚合物材料，主要来源于毛发、羊毛和羽毛等基于蛋白质的生物质。可持续溶解技术的发展对于实现富含角蛋白的生物质的高价值应用至关重要。本研究报道了一种由柠檬酸（CA）和L-半胱氨酸（L-Cys）组成的还原性天然深共晶溶剂（NADES）体系，用于从羊毛中高效提取角蛋白。分子动力学（MD）模拟揭示了溶剂成分之间的关键相互作用，而实验评估则考察了羊毛的溶解效率、角蛋白产率以及再生角蛋白的性质。值得注意的是，CA与L-Cys的摩尔比为2:1时，能在90℃下3小时内使羊毛完全溶解，产生约76%的角蛋白，其中包括58%的水不溶性角蛋白（WIK）和18%的水溶性角蛋白（WSK）。SDS-PAGE分析表明，WIK的分子量分布较宽，而WSK主要低于20 kDa。原位实验表明，最佳溶剂体系在约1.5小时左右可完全破坏羊毛结构。X射线衍射（XRD）结果证实，相对于天然羊毛和WIK，WSK的α-螺旋含量显著降低。傅里叶变换红外光谱（FTIR）、差示扫描量热法（DSC）和元素分析表明，WSK中存在痕量的CA和L-Cys残基，但其仍表现出良好的细胞相容性。这些发现展示了一种从羊毛中提取角蛋白的简单、绿色且高效的方法，为富含角蛋白的废弃生物质的升级利用提供了一条可行途径。
