Types of Enzymes
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| Desizing machine |
Animal source
The enzymes which are obtained from the animal source are called animal-sourced enzymes.
Examples - Degomma, slaughterhouse wastes like liver, clotted blood, pancreas.
Vegetable source
The enzymes which are obtained from the vegetable source are called vegetable source enzymes.
Vegetable source enzymes have further classification as given below Vegetable enzymes are again classified into the following types.
Vegetable source
Malt extracts | Bacterial |
Examples- Diastase, Maltostase, Diastafore | Examples- Raddase, Bidlase, Taka, Arcy |
In enzymatic desizing, the desizing bath consists of the following
ingredients with its role -
2. Common Salt. (increases the stability of enzymes)
3. Wetting agents (help in penetration by decreasing surface tension)
4. Acetic acid (Maintain Acid condition)
After passing through this desired bath, which is kept at a certain temperature and pH range, the cloth is pressed, batched, and stored for roughly 8 hours before being washed hot and cold.
Because enzymes are active only within a small temperature range, a temperature restriction must be maintained during this procedure.
Thermal stabilizers are also utilized, and they operate best around 60°C. Enzymes work best in a slightly alkaline solution, therefore a pH range of 5.5 to 6.5 is required. Acetic acid is used to alter the pH.
The fabric should be compatible with the wetting agent. Use of enzymes and other chemicals Biocatalyst is what enzymes are.
They act to break down starch into smaller molecules quickly. They are also known as Amylases since they function to eliminate waste.
Enzyme | Concentration (GPL) | Temperature | pH |
Malt extract(Vegetable origin) | 3 to 20 | 50 to 60°C | 6 to 7.5 |
Pancreatic(animal origin) | 1 to 3 | 50 to 60°C | 6.5 to 7.5 |
Bacterial(vegetable origin) | 0.5 to 1 | 60 to 70°C | 5.5 to 7.5 |
Amylase is classified into two types -
There is 95 to 99 % alpha-amylase in pancreatic and bacterial enzymes, while in malt extract, the two types are in a 1:5 and 1:6 ratio, respectively.
Process flow
Pass through Desizing bath → Squeezed between roller → Batched → Stored for 8 hours → Hot wash and cold wash
The action of enzymes - ( lock & key mechanism)
Enzyme + starch → Enzyme starch complex (unstable) → Enzyme + Degraded starch → Enzyme + further degraded starch → Enzyme + soluble fragments of starch.
Because starch is made up of two types of polysaccharides,
amylose, and amylopectin, which are both water-insoluble, it must
be converted into a water-soluble component to be removed.
The degree of polymerization (DP) of amylose and amylopectin,
respectively, is 100-120 and 500-1000.
Hydrolysis of starch
Starch (insoluble) → Dextrins( Insoluble ) → Dextrins (soluble ) → Maltose (soluble) → Alpha glucose (soluble).
Commercially, we don't go all the way to the end and instead stick
to dextrin (soluble) to save time and chemicals.
Alpha-amylase attacks amylose in a very random manner, just as it does amylopectin. Beta amylase attaches to one of the broken simple chain's ends and continues to remove the maltose units that are formed.
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| Desizing machine layout |
Questions -
- What are the types of enzymes?
- What are the animal and natural sources of enzymes for desizing?
- What are the alpha and beta-amylase?
- Describe the action of enzymes during desizing processing.
- Describe hydrolysis of starch.
References
6. Wet processing. (2011, August 24). Textile Technology. https://textechdip.wordpress.com/contents/wet-processing/
Arputharaj, A., Raja, A. S. M., & Saxena, S. (2016). Developments in sustainable chemical processing of textiles. In Green Fashion (pp. 217–252). Springer Singapore.
Cenite, M. (2015). Google Books. In The SAGE Guide to Key Issues in Mass Media Ethics and Law (pp. 847–858). SAGE Publications, Inc.
Chemicals used in textile processing. (2013, January 10). OEcotextiles. https://oecotextiles.blog/2013/01/10/chemicals-used-in-textile-processing/
Chemistry of textile manufacturing. (2014, April 29). Worldofchemicals.com; Worldofchemicals. https://www.worldofchemicals.com/448/chemistry-articles/chemistry-of-textile-manufacturing.html
Get to know about chemical processing of textile materials. (2022, May 10). ECHEMI. https://www.echemi.com/cms/640314.html
Kan, C.-W. (2015). Plasma treatments for sustainable textile processing. In Sustainable Apparel (pp. 49–118). Elsevier.
Textile School. (2010, November 10). Fabric wet processing techniques. Textile School. https://www.textileschool.com/343/fabric-wet-processing-techniques/
textileblog. (2020, June 19). Stages of wet processing in textile industry. Textile Blog. https://www.textileblog.com/stages-of-wet-processing-in-textile-industry/
Vigo, T. L. (2014). Textile processing and properties: Preparation, dyeing, finishing and performance: Preparation, dyeing, finishing and performance (1st ed.). Elsevier Science & Technology. https://www.elsevier.com/books/textile-processing-and-properties/vigo/978-0-444-88224-0?country=GB&format=print&utm_source=google_ads&utm_medium=paid_search&utm_campaign=ukshopping&gclid=CjwKCAiAhqCdBhB0EiwAH8M_Gn3kr_d2paqVzccxckWobOsLcwl0cD_Mu6vA5I-eqFARiZwx32eUOxoC-LMQAvD_BwE&gclsrc=aw.ds
(N.d.). Textilelearner.net. https://textilelearner.net/flow-chart-of-textile-wet-processing/
Babu, S. (n.d.). Textile Adviser. Textileadvisor.com. from https://www.textileadvisor.com/2021/12/fabric-desizing-process-types-of.html
Desizing. (n.d.). Kemin. from https://www.garmonchemicals.com/en/textile-chemicals/garment-denim-finishing/enzyme-desizing
Landage, S. M. (2022). Biotechnological approaches in desizing of textile materials. In O. L. Shanmugasundaram (Ed.), Applications of Biotechnology for Sustainable Textile Production (pp. 47–73). Elsevier.
Madhu, C. (n.d.). TEXTILE CHEMROSE. Blogspot.com. from https://textilechemrose.blogspot.com/2015/12/desizing.html
Process of cotton Textile Materials desizing. (2013, September 12). Fibre2fashion.com; Fibre2Fashion. https://www.fibre2fashion.com/industry-article/7064/problems-in-desizing-cotton-textile-materials
Trivedi, Y. (2021, May 9). Textile Desizing process. Textilesphere.com. https://www.textilesphere.com/2021/05/desizing-textile.html
Further reading,
Part 2 Desizing process reactions - Hydrolytic and Oxidation method
Part 3 Three chemicals that carried out desizing
Part 4 Rot steep and Acid steep methods for desizing
Part 5 Alkali desizing
Part 6 Hydrolytic desizing
Part 7 Desizing with the help of the Enzymes
Part 8 Continuous desizing process (Winch and J-box)
Part 9 Desizing of polyester-cotton blends
Part 10 Padroll and padsteam desizing
Part 11 Novel desizing
Writer - Rushikesh Patil (Textile Engineer)
