Fig. 4From: Biotransformation of keratin waste to amino acids and active peptides based on cell-free catalysisScanning electron microscopy images of feathers. a, e Untreated feathers. b, f Feathers were treated with KerZ1 (45.14 KU/mL) at 60 °C for 4 h. c, g Feathers were treated with 0.1% sodium sulfite at 60 °C for 4 h. d, h Feathers were treated with KerZ1 (45.14 KU/mL) containing 0.1% sodium sulfite at 60 °C for 4 hBack to article page