Bleaching and dyeing; fluid treatment and chemical modification – Bleaching – Color stripping or subduing
Reexamination Certificate
1996-09-25
2002-09-17
Diamond, Alan (Department: 1753)
Bleaching and dyeing; fluid treatment and chemical modification
Bleaching
Color stripping or subduing
C008S107000, C510S320000, C510S321000, C510S392000, C510S393000, C510S530000, C426S623000, C426S648000, C162S072000, C162S091000, C162S004000, C162S005000, C162S158000, C435S263000, C435S267000, C435S277000
Reexamination Certificate
active
06451063
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention is directed to methods comprising the use of cellulases in industrial processes and compositions therefor. In particular, the present invention is related to treating textiles, e.g., laundering and processing, with cellulase derived from
Thermomonospora fusca
which is particularly well suited for that purpose. The present invention is further related to the use of cellulase derived from
Thermomonospora fusca
to enhance the digestibility of animal feed, in detergents, in the treatment of pulp and paper and in the production of starch and treatment of by-products thereof.
Cellulases are enzymes which hydrolyze cellulose (&bgr;-1,4-D-glucan linkages) and produce as primary products glucose, cellobiose and cellooligosaccharides. Cellulases are produced by a number of microorganisms and comprise several different enzyme classifications including those identified as exo-cellobiohydrolases (CBH), endoglucanases (EG) and &bgr;-glucosidases (BG) (M. Schulein, Methods in Enzymology, vol. 160, pp. 235-242 (1988)). Current theory holds that the enzymes within these classifications can be separated into individual components. For example, microbial cellulase compositions may consist of one or more CBH components, one or more EG components and possibly &bgr;-glucosidase. The complete cellulase system comprising CBH, EG and BG components synergistically act to convert crystalline cellulose to glucose. The exo-cellobiohydrolases and the endoglucanases act together to hydrolyze cellulose to small cello-oligosaccharides. The oligosaccharides (mainly cellobioses) are subsequently hydrolyzed to glucose by a major &bgr;-glucosidase.
Cellulases and components thereof, used either singularly or in combination, are known to be useful in detergent compositions and for treating textiles. In the textile industry, during or shortly after the manufacture of cotton-containing fabrics, it is known to treat such fabrics with cellulase to impart desirable properties to the fabric. One purpose of this treatment is to remove fuzz, i.e., untangled fiber ends that protrude from the surface of a yarn or fabric, and pills, i.e., bunches or balls of tangled fibers that are held to the surface of a fabric by one or more fibers. Accordingly, in the textile industry, cellulase has been used to improve the feel and/or appearance of cotton-containing fabrics, to remove surface fibers from cotton-containing knits, and also for imparting a stone washed appearance to cotton-containing denims. In particular, Japanese Patent Application Nos. 58-36217 and 58-54032 as well as Ohishi et al., “Reformation of Cotton Fabric by Cellulase” and “What's New—Weight Loss Treatment to Soften the Touch of Cotton Fabric” Japan Textile News, (December 1988) each disclose that treatment of cotton-containing fabrics with cellulase results in an improved feel for the fabric. It is generally believed that this cellulase treatment removes cotton fuzzing and/or surface fibers which reduces the weight of the fabric. The combination of these effects imparts improved feel to the fabric.
Clothing made from cellulose fabric, such as cotton denim, is stiff in texture due to the presence of sizing compositions used to ease manufacturing, handling and assembling of clothing items and typically has a fresh dark dyed appearance. One desirable characteristic of indigo-dyed denim cloth is the alteration of dyed threads with white threads, which gives denim a white on blue appearance. For example, after a period of extended wear and laundering, the clothing items, particularly denim, can develop in the panels and seams localized areas of variation in the form of a lightening in the depth or density of color. In addition, a general fading of the clothes, some pucker in seams and some wrinkling in the fabric panels can often appear. In recent years such a distressed or “stonewashed” look, particularly in denim clothing, has become very desirable to a substantial proportion of the public.
Previous methods for producing the distressed look included stonewashing of a clothing item or items in a large tub with pumice stones having a particle size of about 1 to 10 inches and with smaller pumice particles generated by the abrasive nature of the process. Typically the clothing item is tumbled with the pumice while wet for a sufficient period such that the pumice abrades the fabric to produce in the fabric panels localized abraded areas of lighter color and similar lightened areas in the seams. Additionally, the pumice softens the fabric and produces a fuzzy surface similar to that produced by the extended wear and laundering of the fabric.
The use of the pumice stones has several disadvantages, including overload damage to the machine motors, mechanical damage to transport mechanisms and washing drums, environmental waste problems from the grit produced and high labor costs associated with the manual removal of the stones from the pockets of the garments. In view of the problems associated with pumice stones in stonewashing, cellulase solutions are used as a replacement for the pumice stones under agitating and cascading conditions, i.e., in a rotary drum washing machine, to impart a “stonewashed” appearance to the denim (U.S. Pat. No. 4,832,864).
A cellulase system derived from the thermophilic, filamentous, soil bacterium
Thermomonospora fusca
has been detected and the biochemical characteristics of that system and components thereof studied (Wilson, Critical Reviews in Biotechnology, Vol. 12½, pp. 45-63 (1992)). One specific endoglucanase component of the
T. fusca
system, E5, has been sequenced (Lao et al., J. Bacter., vol. 173, pp. 3397-3407 (1991)), and its disulfide arrangement and functional domains described (McGinnis et al., Biochemistry, vol. 32, pp. 8157-8161 (1993)). McGinnis discloses that E5 treated with protease from
Streptomyces lividans
results in a 14 kD cellulose binding domain and a catalytically active 32 kD fragment which had lost the ability to bind to cellulose. Pure catalytically active
S. lividans
protease treated E5 was shown to have similar activity to intact enzyme on CMC. However, mixtures of catalytically active E5 fragments, when combined with intact E3 from
T. fusca
or intact E3 and CBHI from
Trichoderma reesei,
showed decreased performance to similar mixtures containing intact E5 instead of the fragment (PCT Publication No. 96/00281).
Despite intensive research related to the use of cellulases in industrial processes, cellulases known and used in the art have shown significant drawbacks. For example, many cellulases have been problematic due to low activity, poor alkaline or acid stability, poor temperature stability and poor oxidative stability. Surprisingly, Applicants herein have discovered that the E5 cellulase possesses a complement of characteristics which makes its use particularly desirable in certain industrial applications.
SUMMARY OF THE INVENTION
According to the present invention, a method of treating cellulosic material is provided comprising contacting the cellulosic material with a cellulase obtainable from
Thermomonospora fusca
corresponding to E5, a truncated E5, or a derivative thereof. In a process embodiment of the invention, the cellulosic material comprises cellulose containing fabric and the result of the method is to produce a stonewashed effect or an improvement in the feel and/or appearance of the fabric. In an alternative process embodiment of the invention, the cellulose containing fabric is contacted with an aqueous solution containing a detergent composition comprising a cellulase obtainable from
T. fusca
corresponding to E5, a truncated E5, or a derivative thereof. In yet another process embodiment of the invention, the cellulosic material comprises wood pulp and the addition of cellulase facilitates the production of paper products therefrom. In yet another process embodiment of the invention, the cellulosic material comprises animal feed and the method results in an increase in the digestibility or value of said animal f
Clarkson Kathleen A.
Swanson Barbara
Winetzky Deborah
Diamond Alan
Genencor International Inc.
Genencor International, Inc
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