Bacterial degradation of sericin for degumming of silk fibers–A green approach

Biodegumming is the process of degradation of sericin and its subsequent removal from the surface of silk fibers using microorganisms. Two proteins, viz., fibroin and sericin, make up the silk fiber. Fibroin is the fiber whereas sericin is the glue-like protein coat present on the surface of the fiber that needs to be removed. During the conventional degumming process, chemicals such as soap and soda are used for the removal of sericin from the fiber. This treatment requires a large quantity of water for the removal of the chemicals used. Also, the waste water released into the environment can lead to water pollution. In the following study, a microbiological degumming process was used for the silk fiber, using various bacterial cultures. Nine isolates were checked for their degumming activity. The biologically treated silk was found to be shinier, smoother, softer, and lustrous as compared to the chemically treated silk. Two promising isolates were identified. The treated silk was also tested for parameters like tensile strength and elongation. Silk was also tested for color fastness after dyeing with turmeric. As compared to the chemical process, the microbiological process was found to be more efficient, cost-effective, rapid, and most importantly, environment friendly.