What Functions Do Enzymes Play In Hemp Spinning And Dyeing

With human beings Spin With the continuous improvement of product performance requirements and the increasing environmental awareness, the new concept of green textiles was born. The development and application of new pollution-free new textile materials which are harmless to human body and the production process that will not bring environmental pollution are the important prerequisite for international trade in the future. [1] is also the trend of future development. As an important part of the textile industry, the linen textile industry, especially the hemp textiles mainly made from foreign exchange, finds the intersection with biotechnology and is the guarantee for its sustainable development. Biological enzyme is a biocatalyst which is fermented, extracted and refined by non-toxic microorganism. It has no toxic and side effects. It is easy to use in technology. It does not need high temperature, high pressure, strong acid, strong alkali and strong oxidant. It is easy to be biodegraded without environmental pollution and has specificity of enzyme. These unique advantages have won a place in the hemp textile industry, and will be the future. industry The inevitable trend of development.

1. An overview of biological enzymes

Enzymes are catalytic substances produced by living cells in living organisms. Compared with inorganic or organic catalysts such as acids and alkaloids, enzymes are highly efficient and highly specific catalysts, and their chemical essence is protein. This indicates that enzymes are a special life catalyst.

1.1, the main factors that affect the enzyme reaction.

Effects of 1.1.1 and inhibitors

Inhibitors have a very important effect on the rate of enzyme reaction. Inhibition can be divided into irreversible inhibition and reversible inhibition. There are 2 kinds of irreversible inhibitors in common inhibitors. One is the reagent that reacts exclusively with the specific (side chain amino acid) group. The other is a specific reagent that modifies the specific site of the enzyme according to the action mechanism of the enzyme.

The influence of 1.1.2 and pH value

Enzyme reaction is carried out under certain conditions. Acid and alkali not only affect the stability of the enzyme, but also directly affect the catalytic activity of the enzyme. The enzyme has a certain range of pH stability. Beyond this range, the enzyme will become denatured.

Effect of 1.1.3 and temperature

Temperature can not only change the speed of enzyme reaction itself, but also lead to denaturation of enzyme protein. The rate of enzyme reaction increases with the increase of temperature. However, when the temperature exceeds the optimum temperature, the reaction rate decreases with the increase of temperature. Moreover, because temperature causes protein deformation to accumulate over time, the optimum temperature measured by different reaction time is often different.

1.2. Stability and preservation of enzymes

1.2.1, enzyme dosage forms

Enzyme preparations are often supplied in 4 forms, namely, liquid enzyme preparations, solid enzyme preparations, pure enzyme preparations and immobilized enzyme preparations. Because of the characteristics of enzymes, how to improve the stability of enzymes and extend their effective period is a problem to be solved in various industries.

1.2.2, factors affecting the stability of enzyme

Temperature

Most enzymes can be used, treated and stored at low temperature (0~4 C). However, the stability of some enzymes' advanced structure is related to the hydrophobic bond; many enzymes can be frozen in liquid nitrogen or -80 C; freeze-drying is also a good and effective method.

2. PH value and buffer solution

Most of the enzymes are stable within their specific pH values, and they fail rapidly beyond this range. The type of buffer sometimes also affects the stability of the enzyme.

Enzyme protein concentration

The stability of the enzyme is different from that of the enzyme. In general, the enzyme protein is relatively stable at high concentration, and it is easy to dissociate, adsorb and even lose the surface deformation at low concentration. Oxidation

Certain enzymes are sulfhydryl enzymes, which may be inactivated in air due to sulfhydryl oxidation. In this case, adding 1mmol/L EDTA or DTT can help to increase stability. {page_break}

Methods of 1.2.3 and stabilizing enzymes

At present, there are several ways to stabilize enzymes: adding substrate inhibitors and coenzymes, adding SH protectants, adding surfactants, adding some low molecular inorganic ions, and immobilizing enzymes.

　 2. Application of enzyme in linen textile industry

2.1, application history

Biological application for hemp degumming can be traced back to sixth Century BC, "Dongmen pond, which can retting ramie", that is, directly immersing ramie in water, and using water and hemp to grow and propagate on the network of microbes.

In the 50s of last century, the research on the leaching of bast fiber mainly focused on the separation of microorganisms and their enzymes with degumming ability. In 1958, AE.M.M proposed the use of pectinase for degumming of hemp (such as linen, hemp, ramie). After 60s, the study of pectinase gradually deepened; in 1972, first reports of pectinase producing microorganisms or pectinase preparations were used in the degumming industry in 1972; in 1973, pectinase was divided into two groups according to the pectinase mechanism, namely pectin esterase and depolymerization enzyme; in 1990, a strain of Bacillus pectate lyase was isolated, which made a great contribution to the degumming of ramie [1]. At the same time, with the continuous development of biotechnology and people's further pursuit of the performance of bast fiber fabrics, the biological finishing technology of bast fabrics has emerged at the historic moment, such as enzyme washing, enzyme desizing, scouring, bleaching, waste liquid treatment, biological soft hemp and modification.

2.2. Applicable enzymes

The main component of hemp fiber is cellulose, which belongs to natural cellulose fiber and cotton fiber. The difference is that the non cellulosic component (collectively referred to as colloid) of hemp fiber is high. It also contains hemicelluloses, pectin, lignin and other substances. The linen fibers used in textile industry are fibers separated from some of the original hemp and almost all of them. Therefore, the enzymes that can be used in the processing of hemp textiles include pectinase, hemicellulase, cellulase, lignin enzyme, catalase, amylase and laccase.

2.3, application area

2.3.1, degumming

At present, the degumming methods of hemp fiber include chemical degumming, microbial degumming and biological and chemical degumming. The utilization of enzyme in degumming is mainly based on the specificity of enzyme, and its degumming principle is as follows.

(1) the enzymatic degumming of hemp fiber is used to dilute the enzyme in water and retting the original hemp for degumming. Compared with conventional chemical degumming, the degumming rate and strength of microorganism are improved, and the residual gum is reduced. The refined hemp fiber has loose and soft handle, which greatly improves the spinnability of hemp fiber, and the yarn and grain of Mao Yu are reduced and the evenness is uniform. Besides, the energy consumption of the degumming process is reduced, the cost is reduced, and environmental protection is beneficial.

(2) hemp fiber bio chemical degumming combined with enzyme activity (mainly pectinase and hemicellulase) decomposes most of the colloids in the raw hemp, and then degumming with a part of the chemical process to produce the refined hemp. During the degumming process, the biological enzyme treatment before alkali boiling can make the binding between the gum and the fiber loose, which is conducive to the removal of the gelatin during alkali boiling. Its advantage is that it can greatly reduce environmental pollution, reduce energy consumption and chemical consumption, fiber damage is small, the quality of refined lees is excellent, and fluffy and soft handle.

(3) hemp fiber chemical biological degumming combined with chemical pretreatment can remove fat wax, some pectin, hemicelluloses and lignin, which is conducive to the attack of enzymes on the substrate in the subsequent process, and then fully utilize the specificity of biological enzymes to remove colloid which is difficult to remove from alkali cooking. Moreover, enzyme treatment can increase lateral expansion, increase pore volume and expand the surface area of lignin, so as to facilitate oxidant to easily contact with gum without damaging fibers during peroxide bleaching. The degumming method has the advantage of biological fiber chemical degumming as well as the properties of biological enzyme modified hemp fibers.

2.3.2, biological soft linen

Because the degree of crystallinity of hemp fibers is generally high, the rigidity is large and the softness is poor, resulting in poor yarn cohesion. Moreover, in spinning process, the transfer frequency of fibers is low, and after fiber degumming, a small amount of gum remains. If glue, lignin and so on, the fibers will not be easily combed, entangled, and produce silk and hard bars. For this reason, before emulsified spinning, it is necessary to use emulsified oil for two times to oil and stack, so as to reduce fiber rigidity and increase fiber softness, so as to improve and improve spinnability. However, because emulsified oil is saponified, it is not resistant to hard water. If the emulsification conditions are not properly controlled, the emulsion will be broken down and the spinnability of the fibers will be reduced. The compound biological soft linen (CDF cellulase and surfactant A and B), which is mainly composed of enzyme CDF, can be used for spinning pretreatment of refined hemp. It can not only reduce the crystallinity and rigidity of fibers by using cellulase to denudate the hemp fibers, but also avoid or reduce the common defects such as hairiness and broken ends in spinning process.

2.3.3, enzyme finishing

Biological enzymes are widely used in textile finishing, such as denim sand washing, biological polishing, wool anti felting treatment, etc. The purpose is to improve the fabric's surface properties and handle, improve the fabric's water absorbency, improve the fabric's affinity with dyes, color rendering rate and chromatic light [6]. {page_break}

Biological polishing finishing

Bipolishing finishing (also known as biologically clean) is a new enzyme catalytic finishing technology, mainly used for cellulose containing fabrics and clothing finishing. The enzyme hydrolyzed the fiber surface of the fabric with controlled partial hydrolysis, which greatly reduced the fuzz on the surface of the fabric, thus improving the surface properties of the fabric [7].

Enzyme washing

The application of biological enzyme washing in the finishing technology of ramie is a new field that has been recognized by Chinese counterparts in the 90s. Because the fiber is prone to prickle when it is in contact with the skin, it is a new technology to remove the prickle sensation of ramie. Cellulase based enzymatic hydrolysis is a new technology. Enzyme washing can change the microstructure of cellulose fibers, widen the longitudinal cracks of hemp fibers, increase the pores, facilitate the penetration of softeners into [8], reduce the bending rigidity of hemp fibers, improve drapability, soften the handle, and eliminate the itchy sensation [9]. As a result, the handle of the fabric is obviously improved, and the luster is soft, and has good drape and wrinkle resistant [10].

Desizing

Traditional desizing is alkaline, acid or oxidizing agent. Improper operation will cause serious loss of fabric strength, and acid and alkali oxidizing agents will pollute the environment. The use of enzymes such as amylase desizing can not only save chemical raw materials, shorten the processing time, but also reduce labor intensity and improve product quality [6].

Bleaching

Cellulase bleaching of cellulose fiber fabrics can be carried out in 2 ways: first, direct destruction of natural cellulose for bleaching, such as in the presence of H2O2 and O2, the decolorization of dyes by peroxidase and laccase; the two is to change starch into glucose and produce H2O2, and then use indirect oxidation bleaching, and the enzyme used is glucoamylase and glucose oxidase. The mechanism is that starch is converted into beta -D glucose under the action of glucoamylase, and beta -D glucose produces H2O2 and gluconic acid under the action of glucose oxidase. On the one hand, H2O2 bleaching fabric, on the other hand, gluconic acid can chelate with metal ions to make the bleaching bath stable and prevent fiber embrittlement. Although the whiteness of the fabric bleached by enzymatic bleaching is slightly worse than that of conventional alkaline bleaching with the same concentration H2O2, its bleached fabric feels soft and thick [6].

Dyeing

After degumming and dyeing with cellulase, the fiber or fabric became porous and loose, which increased the dyeing rate, but dissolved the non qualitative area. The affinity of dye to the matrix decreased, the effective volume of dye molecules decreased, and the dye uptake decreased by [6].

Waste liquid and waste treatment

To some extent, the wet processing of textile will bring a burden to the environment -- waste liquid and waste disposal [6]. Practice has proved that enzyme can also play a great role in the treatment of three wastes. The trend is to use immobilized enzyme or immobilized microorganism instead of the traditional microbial explosion gas method [2]. 2.4, the advantages of biological enzymes in the linen textile industry. {page_break}

Enzyme is a biocatalyst instead of traditional chemical catalyst. It has the characteristics of biodegradability and reutilization, and meets the ecological requirements. Wet processing of textiles with enzymes not only improves the wearability, but also does not damage the skin. It also has low energy consumption and easy biodegradation of waste liquid, which is in line with the requirements of ecological textiles. If chlorine free bleaching is used, the development of chlorinated enzyme free H2O2 bleaching can reduce chlorine production in textile bleaching and dyeing process, reduce environmental damage, improve workshops environment, and prevent phosphorus and silicon containing stabilizers from remaining on fabrics. Biological treatment of hemp fibers by using a compound enzyme can greatly improve fiber splitting, fiber softness, uniformity and spinnability are also greatly improved. A biological enzyme can replace pumice to wash pumice in Indigo jeans, which means less damage to clothes, less wear to machines, and less [9] of pumice dust.

　 3, the possible problems and Countermeasures in the application of enzymes

3.1. Problems that may arise

This is mainly reflected in the following aspects: (1) enzyme activity specificity and the most suitable conditions often fail to meet the requirements of the production process [2]; 2. Enzymes are proteins that are prone to denaturation and failure, and generally can not withstand the test of high temperature, strong base, strong acid, organic solvents and time. [2], the production cost of enzyme is high, and it is difficult to transport and preserve. 4. There is a serious disconnection between the enzyme manufacturers and the specific application areas. For example, the enzyme used in the biological treatment of hemp fiber is mainly derived from enzymes used in food processing, with low vitality and single components. Natural enzymes are highly efficient and highly specific catalytic properties, and have been widely applied in various fields, but they are not perfect.

3.2, countermeasures

In order to meet the needs of production practice, the application of enzymes is improved. value Enzyme modification is usually carried out. The most direct way to transform enzymes is to transform them from the chemical structure level of enzyme molecules, namely enzyme molecular engineering. It includes adjusting the active structure of enzymes, changing the microenvironment of enzymes, introducing hydrogen bonds, hydrophobic bonds, salt bridges, strengthening the rigidity and intensity of active structures of enzymes, establishing a selective barrier, avoiding direct contact with the immune system and proteolytic enzymes. Currently, there are 3 methods for enzyme molecular modification: (1) chemical modification; second, deformation induced conformation reconstruction, or bond renaturation conformation reconstruction; third, protein engineering, namely gene location mutation method based on genetic engineering.

4, prospect

The application of biological enzyme in the linen spinning industry, no matter in the pretreatment of fibers, the improvement of the spinnability of raw materials, the improvement of product properties, or the environmental protection, determines that the combination of the linen textile industry and biotechnology will provide favorable conditions for the sustainable and rapid development of the textile industry. And their combination is in line with the international trend of development, and the true meaning of "green textiles" will be born. In the future, as long as we can find a more suitable enzyme source, reduce the cost of enzyme production, make a safe and effective dosage form and establish an optimized high-yield technological condition [2], and fully combine the 2 fields, we can give full play to their respective values.