Enzyme washing
{{Short description|Textile processing technique}}
Enzyme washing or "bio stoning" is a textile manufacturing technique in which cellulase enzymes are applied to denim. As with traditional stone washing, the intended effect is a faded appearance and softer feel.{{cite journal |last1=Patra |first1=A.K. |last2=Madhu |first2=Amit |last3=Bala |first3=Neeraj |title=Enzyme washing of indigo and sulphur dyed denim |journal=Fashion and Textiles |date=2018 |volume=5 |doi=10.1186/s40691-017-0126-9 |doi-access=free }} Because the technique relies on biotechnology, enzyme washing is considered an example of textile bio-processing.{{cite journal |last1=Mosjov |first1=Kiro |title=Trends in Bio-Processing of Textiles: A Review |journal=Advanced Technologies |date=2014 |volume=3 |issue=2 |pages=135–138}}[https://www.metrodyeing.com/dyeing/enzyme-washing/ ENZYME WASHING INFORMATION]
Technique
=Mechanism=
In the enzyme wash process, cellulases act on exposed cellulose on the cotton fibers, freeing indigo dye from the fabric.{{cite journal |last1=Bhat |first1=M.K. |title=Cellulases and related enzymes in biotechnology |journal=Biotechnology Advances |date=2000 |volume=18 |issue=5 |pages=355–383 |doi=10.1016/S0734-9750(00)00041-0|pmid=14538100 }} The effect achieved by enzyme washing can be modified by using cellulase of either neutral or acidic pH and by introducing extra mechanical agitation by means such as steel balls.
=Comparison to other techniques=
==Advantages==
Enzyme washing is considered more sustainable than stone washing or acid washing because it is more water efficient. Residual pumice fragments from stone washing demand a lot of water to be eliminated, and acid washing involves multiple wash cycles to produce the desired effect.{{cite web |last1=Trotman |first1=Samuel |title=Future of Wash: Sustainable Solutions for Stone and Acid Wash in the Denim Industry |url=https://denimdudes.co/future-of-wash-sustainable-solutions-for-stone-and-acid-wash-in-the-denim-industry/ |website=Denim Dudes |accessdate=14 November 2020}} The substrate-specificity of enzymes also makes the technique more refined than other methods of processing denim.
==Disadvantages==
In enzyme washing, dye released by enzymatic activity has a tendency to redeposit on the textile ("back staining"). Wash specialists Arianna Bolzoni and Troy Strebe have criticized the quality of enzyme-washed denim compared to stone-washed denim but agree that the difference would not be detected by the average consumer.
History
In the mid-1980s, recognition of the environmental impact of stone washing and increasing environmental regulations drove demand for a sustainable alternative. Enzyme washing was introduced in Europe in 1989 and was adopted in the United States the following year.{{cite web |last1=Marre |first1=Kathleen |title="Stone" Washing Jeans: Cellulases |url=http://webphysics.iupui.edu/webscience/bio_archive/goodfor15.html |website=IUPUI Department of Biology}} The technique has been a subject of more intense scientific study since the late 1990s. In 2017, Novozymes developed a technique to spray enzymes directly on denim in a closed washing machine system as opposed to adding the enzymes to an open washing machine, further decreasing the water needed for the enzyme wash.{{cite web |title=Enzymes make your jeans less thirsty |url=http://blog.novozymes.com/enzymes-make-your-jeans-less-thirsty/ |website=Novozymes}} The recent revival in acid-washed denim in the late 2010s as well as increased demand for eco-friendly denim voiced on social media have made sustainable wash techniques such as enzyme washing even more integral to the textile industry.