Sericin separation from silk degumming wastewater

This study was conducted to the recovery of sericin protein produced during silk degumming process. Sericin waste solution from conventional degumming process in Thailand contained high BOD (4840 mg/L), COD (8870 mg/L) and nitrogen content (0.11%). This indicated protein contamination and high cost for wastewater treatment. To reduce the treatment costs as well as to recover valuable sericin protein, membrane filtration and enzymatic hydrolysis of recovered sericin were studied. The results showed the quality improvement of wastewater (BOD, 158 mg/L; COD, 260 mg/L) as well as that an amount of sericin protein with molecular weight 2427–9863 Da were recovered after membrane filtration process. The recovered sericin was further enzymatically hydrolyzed to obtain sericin hydrolysate (average molecular weight 1046–2795 Da), which is mostly suitable for further cosmetics application.