Corn fibres have emerged as an eco-friendly substitute for synthetic fabrics and are being used for making not just clothes, but also in geotextiles and home textiles. Renuka Tejaswini explains the processes involved in extracting corn fibres from corn starch and its many benefits and applications in the textile industry.

 

For many years, enzymes like amylase from malt extracts have been used to degrade starch-based sizes for cheap and effective desizing, which are also economical.

 

A low-cost and effective biotechnology solution in textile processing has been found and new fabrics have been discovered. To produce those fabrics, yarn and fibre manufacturing are necessary. Experiments are done to extract from various bio-based products which are derived from natural renewable resources (i.e., eco- friendly), which are less dependent on petroleum-based ingredients. The product which acts as an alternative to the synthetic is derived from corn.

 

By fermenting corn starch, which generates lactic acid (i.e., polymer) corn fibres originate. Just corn fibres are made using fermentation of plant sugar. It is not naturally available since it involves chemical transformation. It is renewable because it does not come from a fossil product.

 

Corn fibre description:

Corn fibre is a manmade fibre which has all the advantages of synthetic materials and various properties of natural products such as cotton and wool.

 

The manufacturing of polymer in corn fibre involves process of fermentation, distillation and polymerisation of simple plant sugar (maize dextrose) on an industrial scale. First, the sugars are fermented. After fermentation, products are transformed into a high performance polymer called polylactide, which can be spun or processed into corn fibre.

 

The production and use of corn fibre create less pollution and fewer greenhouse gases.

 

Fig: Eco Corn Fibre Small Ball

 

Conversion of starch:

Corn starch contains about 27 per cent amylase. Starch cannot be metabolised directly by yeast. It should be first broken down into simple six carbon sugars prior to fermentation. For this conversion, the pH of the mash is adjusted to 6.0, followed by the alpha-amylase.

 

The mash is heated above 100c using a jet cooker. The corn mash is kept at the elevated temperature for several minutes by pumping it through a holding tube equipped with a back pressure valve. The mash flows from the holding tube into a flash tank and the temperature is allowed to fall to 80-90c. Now alpha amylase is added and the mash is liquefied for at least 30 minutes. Then, the mash is cooled and glucoamylase enzyme is added. It converts starch into glucose.

Fermentation process:

After cooking, the mash is cooled to 32oc. With the addition of yeast, it is transferred to fermenters. For the growth of yeast, urea is added. Ethanol and dry grind mills are also added to break down the corn protein to free amino acids, which is an additional source of nitrogen for the yeast. Fermentation requires 48 to 72 hours and has a final ethanol concentration of 10 to 12 per cent, pH value decreases to 4, this decrease in pH is important for increasing the activity of glucoamylase and inhibiting the growth of contaminating bacteria.

 

Distillation process:

Distillation is the process of separating ethanol from solids and water in the mash. Alcohol vaporises at 78oc and water at 100oc. Therefore, this difference allows water to be separated from ethanol by heating in a distillation column.

 

Conventional process can produce 95 per cent pure ethanol. At this point, further separation of alcohol and water cannot occur by heat. To blend with gasoline, the remaining 5 per cent water must be removed by other methods. One of the methods is by molecular sieve system with the help of modern dry grind ethanol plants. By this method 100 per cent pure ethanol can be produced.

 

The anhydrous ethanol is then blended with approximately 5 per cent gasoline to make it undrinkable and thus there will not be beverage alcohol tax.

 

Processing stillage:

The solid and liquid fractions remaining after distillation are referred as Whole Stillage. This includes fibre, oil, and protein components of grain and non-fermented starch. First, the thin stillage is separated from the insoluble solid fraction using extruders. Then, the beer column in which ethanol is centrifuged with a stoppered bottle. Between 15 per cent and 30 per cent of the liquid fraction is recycled as backset, remaining is concentrated by evaporation and mixed with the residual solids from the fermentation, finally a thick syrup is mixed with the solids to make a feed product known as Wet Distillers Grains with Solubles (WDGS).

 

PROPERTIES:

         It is a natural flame-retardant fibre.

         It has strength and provides comfort, softness and drape.

         It can be in spun and filament form and in a wide variety of counts.

         It has moisture management property and low odour retention.

         Corn fibre filaments have a subtle lustre.

         It is resistant to UV light, retains strength, colour etc properties overtime.

         Garments in corn fibre have quick drying and show excellent after-wash appearance etc.

         It is completely biodegradable, compostable, burnable (without producing dangerous fumes) and recyclable.

 

 

Fig: Corn PLA Fibre

 

Fig: Corn Fibre Silver

 

Applications:

Corn fibre can be used both with woven and non-woven fabrics.

 

         Apparel: Sports, casual wear t-shirts, fleece, jeans, shirting's, trousers, duvet, jackets, jersey dressing, hosiery etc.

Fig: A Corn based fibre made apparel fibre Fig: Textile Made from Eco-friendly Corn Extract

 

         Home textiles: Blankets, carpets, pillows, duvets, mattresses, draperies etc.

Fig: Corn fibre made carpets

 

         Non Woven's: Used in cosmetics and diapers.

Fig: Corn fibre made diapers

 

         Industrial applications: Geo textiles, agro textiles etc.

Fig: Corn fibre made agrotextiles

 

Other corn fibre products

Fig: Corn Fibre Socks

 

Bibiliography:

1. Dr. Reena Agarwal et.al. "Corn Fibre: A New Fibre on Horizon".

2. R. J. Bothast, M. A. Schlicher, "Biotechnological processes for conversion of corn into ethanol", Appl Microbiol Biotechnol (2005), volumes 19-25.

3. AshokMulchandani,"Applied biochemistry and biotechnology", Volumes 113-116 (12 Issues), spring 2004, ISSN: 0273-2289.

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11. Xkko.eu

12. Textilesinnovationsophiewise.wordpress.com