Degumming of silk fabric with several proteases

A crepe silk fabric was treated with different alkaline, neutral and acid proteases with the aim to study their effectiveness as degumming agents. Proteases were used under optimum conditions of pH and temperature, while enzyme concentration and treatment time were varied in order to study the kinetics of sericin removal. Degumming loss with soap and alkali was 27% wt. Enzymatic degumming loss increased as a function of the treatment time, reaching a value of 25% wt. The surface analysis showed that sericin was completely removed from the warp yarns of the fabric, while the highly twisted weft yarns showed sericin deposits into the internal fibre texture. The HPLC pattern of soluble sericin peptides changed as a function of the type of enzyme used, enzyme concentration and treatment time.