Month: April 2023

Introduction of cellulase:

Biological enzyme preparations are widely used in textile dyeing and finishing due to their high efficiency, specificity, mild reaction conditions, and environmentally friendly processing. Among them, cellulase is the most widely used and successful enzyme preparation.

Cellulase is a general term for a group of enzymes that catalyze the hydrolysis of cellulose to generate glucose. Currently, commercial cellulase is mainly produced by fermentation of strains belonging to two genera, Trichoderma spp. and Aspergillus niger.

According to their properties and functions, the various components of cellulase can mainly be divided into three categories:

(1) Endo-1,4-β-glucanase (endo-l, 4-D-vlucanase, EC3.2.1.4, abbreviated as EG for fungi and Cen for bacteria). This enzyme randomly hydrolyzes the β-1,4-glycosidic bonds in the cellulose macromolecular chain, forming new reducing ends.

(2) Exo-1,4-β-glucanase (exo-l, 4-p-D-jucanase, EC3.2.1.91, abbreviated as CBH for fungi and Cex for bacteria). This enzyme hydrolyzes the cellulose chain from the end, releasing cellobiose sequentially.

(3) β-glucosidase (3-D-～lucosidase, EC3.2.1.21, abbreviated as BG), also known as cellobiase. This enzyme mainly continues to hydrolyze the cellobiose, oligosaccharides, and low-molecular-weight oligomers produced by endo-1,4-β-glucanase and exo-1,4-β-glucanase, generating glucose.

In the 1980s, American scientists first applied cellulase to cotton fabric finishing, and researchers in various countries have since conducted many studies on the application of cellulase in textile processing. Currently, cellulase has been successfully applied to pre-treatment of cellulose fiber fabrics for refining, softening, polishing, and retrograding of denim fabrics.

Application of cellulase in the finishing of cellulose fiber fabrics:

1. Application of cellulase in cotton refining process：
After the desizing process of cotton fabrics, there are still a large number of natural impurities (cottonseed hulls, pectin, waxy substances, proteins, etc.), residual sizing agents, and oil, which results in poor wetting and yellowing of the fabric, affecting its appearance, feel, and subsequent processing. Therefore, cotton fabrics need to undergo refining process after desizing to remove natural impurities. The traditional alkali refining process of cotton fabrics has the disadvantages of high energy consumption, large wastewater discharge, and severe fiber damage, which no longer meets the requirements of modern green textile processing.

The use of cellulase in refining process is an important research direction for scientists in various countries. Cellulase can hydrolyze cellulose, weaken the microfibers attached to impurities, and fall off from the fabric under mechanical action, achieving the purpose of removing impurities. Cellulase can also degrade cottonseed hulls on cotton fibers.

Although cellulase treatment of cotton fabrics can achieve the purpose of removing impurities to a certain extent, the effect is not ideal. In order to further improve the effect of enzyme refining, more and more studies are using cellulase and other enzyme preparations (pectinase, protease, lipase, xylanase, keratinase, etc.) in combination for cotton refining. In composite enzyme preparations, the synergistic effect of various enzyme components can hydrolyze impurities more and faster.

2. The application of cellulase in the softening finishing of cellulose fiber fabrics:
Biological softening finishing is the use of cellulase to hydrolyze cellulose fibers, making them less stiff and improving the softness of the fabric.

3. Application of cellulase in polishing and finishing of cellulose fiber fabrics:
The application of cellulase in the polishing finishing of cellulose fiber fabrics.
The surface of cellulose fibers has many protruding microfibrils, which makes it easy for fabrics to fuzz and pill under external forces and friction, affecting the surface smoothness and feel of the fabric. Biological polishing is a finishing method that uses cellulase to improve the surface smoothness and softness of cellulose fiber fabrics by hydrolyzing the fibers’ surface fluff and microfibrils, making them brittle, so they can fall off from the fabric surface under the friction between fabrics or between fabric and equipment. This finishing can be applied to woven and knitted cellulose fiber fabrics (cotton, linen) and can be carried out at any stage of textile wet processing, mostly after bleaching.

Pete et al. used Trichoderma reesei cellulase to treat cotton fibers and yarns and found that the fibers became smoother and the yarn fuzz reduced after treatment. Sreenath et al. used cellulase, pectinase, and xylanase to treat jute/cotton blended fabrics individually or in combination and found that cellulase treatment alone could remove the jute and cotton fibers’ protrusions, while pectinase and xylanase alone could not. When cellulase, pectinase, and xylanase were used together, cellulase could achieve good polishing effects at a lower dosage, indicating that the addition of pectinase and xylanase has a certain promoting effect on cellulase polishing. Fu et al. found that ethylenediamine can increase the activity, thermal stability, and reusability of cellulase, and improve the polishing effect of cellulase on cotton fabrics.

4. Application of cellulase in denim garment vintage finishing:
Denim fabric is generally made of indigo-dyed pure cotton yarns as warp and undyed yarns as weft, woven into a coarse twill fabric. Due to the poor wet friction fastness of indigo dyes, denim fabric can achieve a “worn-out” fashion effect through a special washing method, which is highly favored by consumers. This finishing process is called denim garment vintage finishing. In the early days, denim fabric was obtained by stone wash, which had some unavoidable disadvantages such as causing clothing to unravel, fabric strength loss, equipment damage, and blockage of drainage systems by small stone particles. Additionally, the washing process produced lime dust, which polluted the fabric and affected the fabric color.

Cellulase has been successfully applied in denim garment vintage finishing. By hydrolyzing the cotton fibers on the surface of denim fabric with cellulase, and under mechanical force, the indigo dye on the surface of the fabric is removed along with the fibers, resulting in an effect similar to stone washing. Cellulase washing can avoid the problems of stone washing and can also provide other advantages. For example, denim fabric washed with cellulase can obtain a more uniform and three-dimensional pattern, bright colors, and improve the fabric’s feel. However, cellulase is prone to combine with the detached indigo dye, which may re-adsorb onto the fabric surface, leading to color reattachment and reducing the washing effect.

Both acid cellulase and neutral cellulase can be used in denim garment vintage finishing. Acid cellulase has a stronger hydrolysis effect on cellulose fibers and higher washing efficiency, but it causes greater fabric strength loss, has poor reproducibility, and is prone to color reattachment. Neutral cellulase has lower activity than acid cellulase, which requires longer processing time or more enzyme to achieve the same finishing effect. However, neutral cellulase treatment causes less fabric strength loss, has good finishing reproducibility, and rarely causes color reattachment. Acid cellulase and neutral cellulase have their own advantages and disadvantages. Due to the lower price of acid cellulase, it is mostly used in denim garment vintage finishing in actual production, while neutral cellulase is only used in the finishing of high-end denim fabrics.

Mamma et al. found that modifying cellulase with proteases can effectively reduce the color reattachment phenomenon during cellulase treatment of denim fabric. Chen et al. discovered that the use of neutral cellulase in denim garment vintage finishing under ultrasonic conditions can improve the washing effect and reduce the processing time.

5. Application of Cellulase in Lyocell Fiber Depilling Process:
Lyocell fiber, also known as Tencel fiber, is made by dissolving cellulose in a solvent called N-methylmorpholine-N-oxide (NMMO) to create a spinning solution, which is then spun into fibers. The solvent can be recycled and is environmentally friendly, making it a “green” fiber for the new century. In addition, Lyocell fiber has the advantages of being soft to the touch, having good moisture absorption, and being strong.

Fiber depilling refers to the process in which some of the fibrils on the surface of fibers detach and split into smaller fibrils due to wet friction between fibers or between fibers and other objects. Fiber depilling is a common issue with cellulose fibers, and Lyocell fibers have the most severe depilling during use. When fibers in a fabric become depilled, the fabric is more prone to pilling and discoloration, which seriously affects the quality and wearability of the fabric.

Cellulase can be used to hydrolyze the microfibrils on the surface of Lyocell fibers, weakening them gradually so that they can be broken and removed by mechanical action, achieving the purpose of depilling.

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Please visit https://xikezymes.com/enzyme-products/textile-enzyme/ or contact textile@xikezymes.com for additional assistance.

Enzymes play an essential role in the textile industry, contributing to the improvement of textile processes’ efficiency, sustainability, and quality. The use of enzymes in the textile industry has increased in recent years, providing several benefits over traditional chemical treatments, such as reduced water consumption, lower energy consumption, and a decrease in toxic by-products. Enzymes are biodegradable and have a high degree of specificity, allowing for selective modification of fibers and textiles.

The textile industry uses enzymes in various applications, including pre-treatment, dyeing, finishing, and bio-polishing. In pre-treatment, enzymes are used to remove natural impurities such as pectins, waxes, and starches, allowing for better penetration of dyes and other chemical treatments. Enzymes are also used in dyeing to improve color fastness, reduce dyeing times, and increase color uniformity. In finishing, enzymes are used to create unique surface effects such as softness, sheen, and stretch, as well as to improve fabric performance, such as water repellency and wrinkle resistance. Finally, bio-polishing is used to improve the appearance and hand feel of cotton-based fabrics, by selectively removing protruding fibers and reducing pilling.

XIKE Enzyme, a leading manufacturer of industrial enzymes, has developed a range of textile enzymes that provide several advantages over traditional chemical treatments. One of the main benefits is improved environmental sustainability, as the enzymes are biodegradable and reduce the amount of water and energy consumed during the production process. Another advantage is increased efficiency and productivity, as the enzymes allow for faster processing times, reduced chemical usage, and improved fiber quality. Additionally, XIKE Enzyme’s textile enzymes have a high degree of specificity, allowing for precise control over the modification of fibers and textiles.

In conclusion, the use of enzymes in the textile industry has become increasingly important, providing several benefits over traditional chemical treatments. Enzymes have a high degree of specificity, are biodegradable, and provide precise control over fiber and textile modification. With the development of new enzyme technologies, such as those offered by XIKE Enzyme, the textile industry can continue to improve its sustainability, efficiency, and quality.