The free enzyme penetrated into wool fiber cortex while the modified enzyme, with a bigger size, was retained at the surface, in the cuticle layer. It was also confirmed that the diffusion of pro teases was facilitated by the hydrolytic action. Scanning electron microphotographs were also used to observe the intensity of the proteolytic attack. In this paper we mainly discussed about the different types of scale removing techniques and advantages of proteolytic enzymes for this process.


The tendency of wool to felt and shrink is mainly due to its scaly structure. The Chlorine-Hercosett is the most widespread process used to modify the scales of wool fibers with the purpose of providing resistance to felting and shrinkage. There have been many attempts to replace this chlorine process by an environmental friendly enzymatic process that would similarly degrade the scales. However; although pro teases are large molecules, their attack is not only limited to the scales; they penetrate inside the fiber causing unacceptable weight and strength loss. It is believed that if the proteases are chemically modified in order to increase their molecular weight, then they will act just on the surface of the fibers, thus providing wool with anti-shrinking behavior. The free enzyme penetrated into wool fiber cortex while the modified enzyme, with a bigger size, was retained at the surface, in the cuticle layer. It was, also confirmed that the diffusion of proteases was' facilitated by the hydrolytic action. Scanning electron microphotographs were also used to observe the intensity of the proteolytic attack. In this paper we mainly discussed about the different types of scale removing techniques and advantages of proteolytic enzymes for this process.


Wool is a complex natural fiber composed mainly of proteins (97%) and lipids (1%), consisting of two major morphological parts: the cuticle and the cortex. The former is composed of overlapping cells (scales) that surround the latter. This scaly structure of wool is responsible, to a great extent, for the tendency of wool to felt and shrink (Heine and Hocker 1995; Feughelman 1997).


Chlorination is a commonly used process to modify the scales of wool fibers with the purpose of providing resistance to felting and shrinkage. There have been many attempts to replace this chlorine process by an environmental friendly enzymatic process that would similarly degrade the scales (Nolte et al. 1996; Heine and Hocker 1995; Silva and Cavaco-Paulo 2003; Cortez et al. 2004).


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G. S. Sivakumar is in II-M. Tech (Textile Chemistry), V. Sivakumar, M. Tech (Phd) and Dr. S. Periyasamy is the Head of the Department, Dept of Textile Chemistry, S.S.M College of Engineering, Komarapalayam, Namakkal, T.N


Originally published in Textile Review, December 2011