Effects of Proteolytic and Lipolytic Enzymes on Untreated and Shrink-resist-treated Wool

There is increasing interest in the use of enzymes in wool-processing, particularly in the context of replacing processes which are nowadays regarded as environmentally unacceptable. The work reported in this paper was initiated in the context of improving wool care in domestic washing and has established techniques for monitoring the complex effects of surfactants on the properties of wool. The same techniques will be of value in the development of new, enzyme-based wool-processing technologies. It is shown that the location of enzymatic attack at a given pH is strongly influenced by the enzyme concentration and reaction time. Polymers applied in the course of shrink-resist finishing can delay enzymatic attack, but, in general, dyeing and oxidative processes leave the fibre more susceptible to enzymatic degradation. Adsorbed protease was not easily removed from treated fibres, and enzyme retained after rinsing and drying is shown to cause further degradation under ambient storage conditions. All washing processes increased fabric-shear stiffness, but treatments involving lipolytic or proteolytic enzymes produced a perceived softening effect, which is attributed to a reduction in fibre-bending stiffness.