Possibilities for recycling cellulases after use in cotton processing - part II : Separation of cellulasesfrom reaction products and released dyestuffs by ultrafiltration

摘要

The adsorption and activity of a total cellulase (Trichoderma reesei) wasmeasured and compared on undyed and dyed cotton fabrics. Recovery ofenzymes from the reaction mixture and by desorption from the cotton substratewas evaluated. About 80% of the initial protein could be recovered.The removal of released products (soluble reducing sugars and dyes) fromthe treatment liquor and subsequent concentration of cellulase proteins wasperformed using an ultrafiltration membrane. Strong protein-dye interactionsmade it impossible to separate efficiently the dyes from the enzymecontainingtreatment liquors. The use of surfactants did not enhance cellulasedesorption from cotton fabric. Although anionic surfactants have a deactivatingeffect on cellulases, this effect seems to be reversible, since after ultrafiltrationthe cellulase activity was similar to that of enzymes desorbed withbuffer only. Humicola insolens cellulases were shown to be much more sensitiveto anionic surfactant than T. reesei cellulases. The use of cellulases thatbind reversibly to cellulose is suggested for achieving more efficient cellulaserecycling and for reducing backstaining by dye-cellulase complexes.