A Biological Approach for Color-Stripping of Cotton Fabric Dyed with C.I. Reactive Black 5 Using Fungal Enzymes from Solid State Fermentation

Abstract

The problem of uneven and faulty dyeing in the finished quality of fabrics is usually tackled through a chemical stripping process to remove the loose dyes from the surface of dyed cotton fabrics. This research work was undertaken to investigate the color stripping of cotton fabric dyed with C.I. reactive black 5 in an environmentally-friendly way using enzymes instead of applying chemicals. Such bio-degradable and economical enzymes were prepared by growing white rot fungus Ganoderma lucidum IBL-05 under the optimized conditions of solid state fermentation (SSF). The biological color stripping process using SSF-enzyme extract was optimized for necessary parameters for effective color strippingsuch as SSF-enzyme concentration, pH, temperature and the duration of the enzyme reaction. The color stripping efficiency of this enzymatic reaction process was evaluated by measuring the K/S values of dyed fabric before and after the color stripping. In the present study 70.81% color stripping of dyed fabric was achieved using a cheaper preparation of crude enzyme extract consisting of three significant enzymes lignin peroxidase (EC 1.11.1.14) (530U/mL), manganese peroxidase (EC 1.11.1.13) (395U/mL) and laccase (EC 1.10.3.2) (68U/mL) under the optimized reaction conditions of stripping medium pH 4.5, at 30°Creaction temperature, and 10 days period of stripping. This biological approach is environmentally friendly as compared to chemical methods used for color stripping in textile industry. Keywords: Cotton-fabric, reactive-dye, color stripping, ganoderma lucidum IBL-05, solid-state fermentation, lignin peroxidase, manganese peroxidase, laccase.