Sustainable Enzymatic Degumming and Natural Dyeing of Silk Fabric Using Papaya (Carica papaya) Latex and Henna (Lawsonia inermis) Extract

Silk degumming is an essential pretreatment process that removes sericin from raw silk to improve softness, luster, and dyeability. Conventional alkaline degumming methods are effective but require harsh chemicals that may damage silk fibroin and generate environmentally harmful effluents. This study investigated a sustainable enzymatic degumming approach using papaya (Carica papaya) latex, a natural source of papain enzyme, followed by natural dyeing with henna (Lawsonia inermis) extract. Raw silk fabrics were treated with papaya enzyme concentrations of 5%, 10%, 15%, and 20% at 40 °C and 45 °C for 60 min. Degumming performance was evaluated through weight loss and CIE whiteness index measurements. The degummed fabrics were mordanted with potash alum or copper sulfate before dyeing with henna extract, and color characteristics together with rubbing and washing fastness were assessed. Degumming efficiency increased from 11.24% to 17.60% with increasing enzyme concentration, while the highest CIE whiteness index (59.52) was obtained at 20% enzyme concentration and 45 °C. Potash alum produced brighter yellow shades, whereas copper sulfate generated darker shades with comparable hue. All dyed samples exhibited excellent dry rubbing fastness (Grade 5), good wet rubbing fastness (Grade 4), and good washing fastness. The results demonstrate that papaya latex-assisted enzymatic degumming combined with natural henna dyeing provides an environmentally friendly alternative to conventional silk wet processing.