SWEET IDEA
Cotton Incorporated’s circular vision includes recycling cotton into glucose.
as fashion reckons with its textile waste impact, the industry is searching for scalable solutions to divert out-of-commission clothing from landfills.
Today, circular streams for cotton-heavy garments like denim include mechanical and chemical recycling to create new textiles and nonwoven products. For instance, Cotton Incorporated’s Blue Jeans Go Green program has collected and converted denim containing at least 90 percent cotton into insulation for buildings, thermal packaging and more. Although widely used, mechanical recycling has limitations. Shredding shortens fibers, narrowing how they can be used. It is also not an answer for multi-fiber textiles, including popular cotton-polyester blends.
As fashion reckons with its textile waste impact, the industry is searching for scalable solutions to divert out-of-commission clothing from landfills.
Today, circular streams for cotton-heavy garments like denim include mechanical and chemical recycling to create new textiles and nonwoven products. For instance, Cotton Incorporated’s Blue Jeans Go Green program has collected and converted denim containing at least 90 percent cotton into insulation for buildings, thermal packaging and more. Although widely used, mechanical recycling has limitations. Shredding shortens fibers, narrowing how they can be used. It is also not an answer for multi-fiber textiles, including popular cotton-polyester blends.
One sweet solution from Cotton Incorporated looks to circumvent some of these challenges. As part of the organization’s work on circularity, researchers within Cotton Incorporated had a “spark of an idea” almost a decade ago to leverage cotton’s chemistry to convert the fiber into a new resource: glucose. Cotton that has been prepped for textile production is about 99 percent cellulose, a polymer composed of glucose molecules. A simple sugar, glucose is a component in not only food products but also chemicals like citric acid and lactic acid.
“We wanted to see if we could take advantage of utilizing recycled cotton in markets other than apparel,” Mary Ankeny, vice president of product development and implementation operations at Cotton Incorporated, told Rivet. “We were trying to think outside the box and think outside of that fiber structure.”
The first step in Cotton Incorporated’s patented enzymatic hydrolysis processes— developed in collaboration with
North Carolina State University professors and graduate students—is preparing the cotton fibers for the enzyme, which can be accomplished either by grinding the cotton or applying a weak acid. A cellulase enzyme is then introduced to break down the cellulose into glucose. After filtering out any residues, the result is a glucose solution.
Because the enzyme only affects cellulosic structures, any synthetic content is left behind. By dividing the two fiber types, this could enable materials like polyester to be captured and recycled separately.
“We really want to divert this textile waste from the landfills, and we recognize that sorting is going to be a big headache and it’s going to add cost to the process,” Ankeny explained. “We developed this technology with the idea that we would not need to sort, that the enzymes and the process is going to be cellulose focused and would just degrade the cellulose in the mix, and then the non-cellulosic material could be separated out and then potentially utilized for something else.”
In 2022, a pilot line was set up at North Carolina State University’s
College of Natural Resources that can process 50 pounds of material at a time, converting roughly 85 percent of cotton inputs into glucose. Currently, the glucose created here is being used for research, including Cotton Incorporated-backed studies centered on transforming glucose into other materials such as acids.
Ankeny sees industrial chemistry as a “good outlet” for the glucose, pointing to the textile industry’s accelerating adoption of bio-based alternatives to petroleum-derived inputs for chemicals. For instance, Archroma’s EarthColors dyes use agricultural waste including cotton biomass from gins, for which Cotton Incorporated supports the raw material supply chain.
The glucose conversion process is designed to be “extremely efficient” in resource consumption, including water, energy and chemicals, and it uses equipment that would already be on hand in chemical or fiber production facilities.
The pilot production line aims to help translate and scale glucose production to the commercial sector. “This is something that the industry could really use,” said Ankeny. “We have 17 million tons of textile material going into the landfill each year. We need some solutions to change that statistic, and I think that there is so much potential in some of this waste.”
Cotton Incorporated has not studied the use of this process for other cellulosic materials such as linen, hemp and wood-based fibers like viscose. However, Ankeny noted that cotton has the most cellulosic content among these and “appears to be the ideal fiber for this process.”
Already, cotton’s byproducts are used for cottonseed oil and cattle feed. Glucose is yet another opportunity to gather more resources from the crop. “Extracting or converting the cellulose to glucose is just one more way to highlight the versatility and the circularity of the cotton plant,” said Ankeny.
WE WERE TRYING TO THINK OUTSIDE THE BOX AND THINK OUTSIDE OF THAT FIBER STRUCTURE.” — Mary Ankeny, Cotton Incorporated