Energy efficient recovery of keratin from poultry feather waste through l-cysteine reduction in CaCl2-ethanol-water system and application of regenerated keratin in textile printing.

Keratin, as an important renewable bio-resource, is widely found in poultry feathers, wool, hair and animal horn. Dissolution of feather keratin is a key process in recycling and utilization of these important biomass materials. This study uses l-cysteine reduction in CaCl2-ethanol-water system to dissolve feather and recover keratin. Results showed that 62% regeneration rate of feather keratin can be achieved under the treatment conditions of 70℃, 1.5 h and bath ratio 1:35. Although a reduction in α-helix structure and crystallinity is seen in regenerated keratin from original feather, the regenerated keratin is able to retain peptide backbone with slightly increased thermo-tolerance from original feather. The dissolving process used in this work can significantly shorten heating time hence reduce the energy required during dissolving process, when compared with prior l-cysteine reduction studies. Regenerated keratin has been investigated for potential use as printing paste in this work. Eco-friendly natural dyes of onion peel extract and gardenia yellow were used to produce colored regenerated keratin. Results showed that regenerated keratin exhibited excellent dye uptakes with natural dye, owning to strong connection between amino acid in keratin and rich phenolic compounds in natural dye. Cotton fabrics printed with colored regenerated keratin showed satisfactory color strength, color fastness and functional property of UV protection. This study provides a novel approach of recycling poultry feather as biomass waste, and a green and value adding application of regenerated keratin in textile printing.