Applications of Cellulase Enzymes

Tyndall, R.M. Application of Cellulase Enzymes to Cotton Fabrics and Garments, AATCC Book of Papers, 259-273 (1991). 

Smaller applications of cellulase enzymes from submerged fermentation are in textile biopolishing, deinking and dewatering paper, processing of fruit juice and other beverages, baking, and alcohol production. 

The precise effects obtained are dependent on the fabric quality, the type of cellulase enzyme and the application conditions, but no mechanical forces are involved in removal of the fibrils. The process has attracted considerable attention and is now one of the main methods of defibrillating lyocell fabrics [94,101-114]. Simultaneous treatment with cellulase and protease enzymes has been applied to the biofinishing of wool/cotton blends [115]. 

A third approach to reducing pilling tendency is applicable to 100 % cotton fabrics. As described in Chapter 17 on enzymatic finishes the use of cellulase enzymes during wet processing can remove enough of the loose fibres in the yams so that pilling is greatly reduced. 

As understanding of the components of the cellulase complex has increased, we can better define the mode of action by which native cellulose is depolymerized. The Ci-Cx model has directed attention to the specific steps in the crystalline cellulose breakdown. The use of nomenclature describing the catalytic function of each specific enzyme should encourage higher standards of purity. The ubiquity of the substrate invites imaginative applications of cellulases. 

As indicated previously, the cost of cellulase enzymes account for a large proportion (60%) of the total cost of cellulosic material conversion [82] the use of surfactants will result in substantial savings [85], This is an area that awaits PBS application. 

Methods of biological utilisation of polyester/cellulose textile blends are based exclusively on the application of cellulolytic enzymes, like cellulases, catalysing the hydrolytic degradation of cellulose to a sugar mixture like glucose or ceUobiose. The recovered polyester components were tested to be recycled in the melt process. ... 

In the treatment of cellulose pulps one essential criterion for a suitable enzyme preparation is that its cellulase activity should be as low as possible, or preferably absent completely. As even extremely low cellulase activities may ruin pulp quality, Trichoderma enzyme preparations are unlikely to be suitable for these applications. Many bacterial and fungal enzymes with low cellulase activity have been shown to be suitable for treatment of pulps 14, 15, 16,17), Regulation of the often synchronous production of cellulolytic and hemicellulolytic enzymes in micro-organisms is not well understood, and is further complicated by substrate cross-specificity of these enzymes. Enzymes with both endoglucanase and xylanase activity have been reported for bacteria 18, 19) and fungi 20, 21, 22), In addition to selection of strain and... 

Cost sensitivity studies have shown that the successful commercialization of cellulase-based processes, such as the conversion of cellulose to fermentable sugars, is highly dependent on the cost of enzyme production (i). Because fungal -D-glucosidase (EC 3.2.1.21) is the most labile enzyme in this system under process conditions (2), and k to efficient saccharification of cellulose, this enzyme was targeted for application of stabilization technology, both through chemical modification and immobilization to solid supports. 

Novo Nordisk has also introduced another application of the laccase formulation, namely for stonewashing in combination with cellulase. It enhances the abrasion effect. In this case, a lower dose of the enzyme/mediator slurry is sufficient. Low doses have a mild bleaching effect though the end-result doesn t look like bleaching. Instead the denim looks as if it has been subject to more abrasion. Cellulases can give a stonewashed look to jeans but they have certain limitations when used on their own. If denim finishers want a highly abraded effect, they usually prefer a combination of cellulases and stones to obtain the desired level of abrasion. With the laccase slurry stones are no longer needed. 

The observation47 that the stability of the secondary-ordered structure of xanthan (and as a consequence, its susceptibility to hydrolysis by cellulase) is a function of temperature, pH, and ionic strength has allowed the application of enzymic techniques to structural analysis. Xanthan is hydrolyzed in salt-free, aqueous solutions at elevated temperatures that is, hydrolysis occurs if the chain is unordered. It was proposed that, at lower temperatures and in the presence of salt, the small side-chains organize around the (1 ->4)-/3-D-glucan backbone and protect it from hydrolysis. 

Enzymatic desizing is one of the oldest nonfood applications of commercial amylases. Another type of enzyme, microbial cellulases, has developed within the textile industry as a tool for fabric finishing, in particular for denim garment finishing. Cellulases can achieve the fashionable worn look traditionally obtained by the abrasive action of pumice stones, ie, stone-washing. 

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