Introduction
The textile industry is one of the most important industries in India as it provides employment to a large number of people directly and indirectly and forms a good part of the GDP of India. On the other hand, the textile and apparel industry are blamed for its role in environmental damages caused by its processes. This environmental damage starts from the production of fibres to the chemical processing of final products. Also, the products cause damage to the environment when they are disposed of after usage.
Biodegradable natural fibres
One of the ways to reduce this damage is the use of bio-degradable, renewable fibres for the production of apparel, technical textiles etc. The most commonly used biodegradable fibres in the textile industry are cotton, wool, silk, jute, flax etc. Considering the carbon footprint, the fibres extracted from jute, flax, hemp, ramie etc., which are much less than cotton and wool, more and more of these fibres should be utilized in textile products.
Table 1: Environmental Impact in Agriculture Production Processes.
Application of Biotechnology
Nowadays, our lives are increasingly changed by the widespread application of high and new technologies. Biotechnology is such a technology, which offers the textile industry the ability to reduce costs, protect the environment, address health and safety, and improve quality and functionality. Especially as more and more strict laws and regulations on the waste water discharge were established and implemented, there is a golden opportunity for biotechnology to replacing the traditional textile processes.
Biotechnology is the application of living organisms and their components to industrial products and processes. In another definition it is mentioned that in pure scientific terms biotechnology is defined as application of biological organisms, systems to processes to manufacturing and processing industries. In textile manufacturing the use of enzymes has a long tradition. The first microbial amylases were used in 1950s for the removal of starch sizes, which today is routinely used by the industry.
Major areas of application of biotechnology in textile industries are:
- Advances in plant biotechnology
- Bio-polishing
- Biotechnology for bast fibre
- Biotechnology in protein fibres
- Biotechnology in textile wet processes
- Biotechnology in garment processing
- Biotechnology in wastewater treatment
Enzymes are natural bio-catalyst that have great potential in catalysis of chemical compounds decomposition and synthesis. Enzyme tested and used in different areas of the textile industry bring many advantages and allow achievement of still unattainable results. The possibility of mutual combination of enzymes with different substrate specific action broadens the area of use. These advantages have initiated the recent development of tailor-made enzymatic mixture for bast fibre processing.
In fibre extraction biotechnology can play a very important role. Various workers have reported positive influence of biotechnology, such as enzymatic degumming of silk with Sericinases, softening of jute with Cellulases and Xylanses, extraction of alfa fibres (Stipa tenacissima L) by using Pectinase and Xylanase, which resulted in fibres with better mechanical properties. In Himalayan region a large number of plants are grown which can be used for extraction of textile grade fibres. The conventional way of fibre extraction, practiced by the local people, produces coarse fibres which can be used for producing ropes, wall hangings etc. which has a very limited market.
Our earlier studies have shown fibrous plants like Vimal, Ramie, Sunhemp and fibres extracted from waste materials such as Pineapple leaves, Banana plants, Pine needles, Pareli (remaining part of plants after harvesting, burning of which cause havoc to the environment) can be utilized for value added products by improving the method of extraction. As conventional retting process needs water and long time, the biotechnology can play an important role in getting high grade fibres from these plants, without damaging environment (water after retting are not drinkable and smells very bad). Increasing demand for quality and reproducibility of fibre processing and end use parameters gradually highlighted and the imperfection caused by seasonal differences of weather conditions during crucial period of field dew retting.
The decisive influence of weather as well as more and more visible changes of climate led to the reasonable problems within the whole cultivation and processing spheres. All these facts underline the need to find a simple, guaranteed process to cut the influence of climate and bring about the possibility of a complex, waste-less utilization of cultivated crops. Biotechnology, more specifically, selective enzymatic process seems to be a clear answer.
During the dew retting process enzymes must be able to attack the natural components of blast plant stalk such as pectin and lignin to support extraction of fibres from stalk building bundles. The main enzymes acting in retting process are pectinase, xylanases and cellulases.
Supported by specific condition of treatment an additional wet processing step could be the most effective alternative avoiding the non-governable climate and weather conditions. In comparison with the direct field application and additional drying step is needed. It is also necessary to avoid risk of fibre agglomeration which would negatively influence the resulting fibre quality such as length and fineness.
Generally, these bast fibres are longer and coarser and cannot be processed by conventional cotton spinning machines. A process is followed to convert these fibres smaller and finer so that the same can be processed by cotton/worsted system individually or after mixing with cotton. This process is known as cottonization. The countries which are main producers of textiles and apparels especially, so called, low wage countries majorly have cotton spinning and wet processing facilities. These facilities can be utilized to produce various fashionable niche products using these cottonized fibres blending with cotton. One of the possibilities for the spinning by use of OE or Ring spinning technology. As an alternative, material friendly bast fibre cottonization procedure, based on combination of enzymatic pre-cottonization followed by a gentle mechanical processing using (e.g. REA120 by Rieter) has been used in commercial scale.
This intervention can increase the income of the local people and prevent them from shifting to cities for income. We propose to produce these bio products and use them for extraction of fine and superior quality of fibres from the fibrous plants available in different parts of India including Himalayan region.
Genetic engineering methods are being investigated with their potential to produce new kind of textile fibres. They are those systems that can produce monomeric protein molecules in solution from appropriately engineered genes. Milk fibres and spider web fibres are some of the fibres produced genetically.
Extraction of keratin-degrading enzyme suitable for use in shrink proofing treatment for wool was isolated from mold. The enzymes act preferentially on the cuticle that is responsible for felt shrinkage, it gives woolen fabric an excellent resistance to shrinkage without weakening the fibre or damaging the hand. The fibroin filaments of cocoon silk are naturally gummed together with the protein sericin. The removal of sericin from raw silk is known as degumming. Enzyme degumming involves proteolytic degradation of sericin using a specific protease, which does not attack fibroin.
Bacterial Cellulose
Bacterial cellulose (BC) or microbial cellulose with a 3D fibrous network structure is found to be 100 times smaller in scale than the plant cellulose. Bacterial Cellulose produced by specific type of bacteria is an organic compound with general formula (C6H10O5)n. BC can be produced by several species of Gram-negative bacteria, particularly from the genera Acetobacter, Gluconobacter, Sarcian ventriculi and Agrobacterium.
Additionally, members of the genera Komagataeibactor (bacteria that consume Kombucha tea and other fermentations) and Gluconacetobactor are employed to produce bacterial cellulose. To cultivate BC, both nitrogen and carbon sources are crucial along with the yeasts that co-exist with the microorganisms. Nitrogen acts as a vital nutrient, enhancing microorganism growth, while carbon serves as the metabolic substrate for the cells. Common teas such as green tea, black tea and orlong tea, due to their caffein content, can provide the needed nitrogen. Meanwhile, various sugars such as glucose, fructose, peptone and their derivatives can serve as carbon source. Utilizing BC derived from biomaterials, especially biowaste, can address waste disposal issues, reduce greenhouse gas emissions and foster more sustainable fashion and textiles.
Artificial leather
Artificial leather has become very popular due to resistance from the customers regarding killing of animals for leather. Leather tanning process is highly toxic and detrimental to ecosystem. In addition, leather production is resource intensive. For example, manufacturing a pair of leather boots requires approximately 25000L of water and 50.2 m2 of land. Additionally, there are significant greenhouse gas emissions linked to animal agriculture. Artificial leather is primarily produced from polymers such as polyurethane (PU) and polyvinyl chloride (PVC). The artificial leather leads to environmental pollution, especially during wet processing. Further the biodegradation of artificial leather from PU or PVC can take several hundred years. The leather industry needs alternative materials those are renewable and biodegradable. Bio-based leather, cultivated from vegetable matter, offers a solution to these challenges. Further, this bio-based leather can be integrated with the existing textile materials such as fabrics and traditional leather.
Use of Biopolymers
The use of biopolymer offers several benefits, including the manufacture of an eco-friendly final product with cheap production costs. A lot of work has gone into making bio-textiles that can meet the needs of the future, like ensuring their superiority in all respects and acquiring textile substrates with prospective capabilities like anti-microbial, fireproof, UV resistant, Conductive to electricity and very hydrophobic. It is important to note that working with bio-polymers can be challenging. For example, chitin can be extracted from crustaccan shells, insect cuticles or fungal biomass.
Based on the source, it will vary in molecular weight, degree of deacetylation (DD), purity, distribution of charged groups and crystallinity. This variation holds true for all biopolymers. As a result of material inconsistency, each bulk material requires unique processing conditions, which complicates controlled manufacturing. Despite the aforementioned challenges, the intrinsic benefits cannot be overlooked: it is for this reason the macrofibres containing biopolymer such as chitosan, alginate, cellulose/chitin, alginate/carboxymethyl (CM) chitosan etc. have been previously fabricated utilizing traditional fibre processing techniques.
Biopolymer nanofibers can be used as particle filters in vivo, nanocomposite reinforcing fibres for nanotechnology sutures, filters for metal recovery, as templates and in chemically and biologically protective clothing.
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