Study On The Modification Of Wool With Transglutaminase

Chlorine and its derivatives are often used in traditional anti-felting finishing of wool. But the chlorine-Hercosett treatment shows the easy absorption of chlorine and gives the yellowing of wool, big damage to wool fiber, environmental pollution and harmful to our health, etc. Growing environmental legislative pressures and rising waste water costs have brought the enzymatic treatment of wool materials to the center of attention as a possible alternative to chlorine treatments. But proteolytic reaction of protease to the wool, either the proteases from mammals or microorganisms, was desquamation model.According to the desquamation model, protease prior to catalyze hydrolyzation of intercellular cement (the cell membrane complex, CMC) globate protein of wool and made protein cells (including scale cells and cortex cells) peel off. Protease treatment is difficult to control within scale and would result in the damage to the wool because CMC globate protein of wool was of vital importance to strength of wool fiber. Therefore, wool bio-finishing with protease was not yet implemented at an industrial scale. The application of protease on anti-felting finishing of wool wouldn’t have industrial and practical means until the damage to the wool fiber can be controlled.Transglutaminases (EC 2.3.2.13, referred to as TGase, or TG) are aminoacyltransferases that are found widely in a host of different organisms including mammals, plants and microorganisms. Transglutaminases catalyse an acyl transfer between peptide-bound glutamine (acyl-donors) and a suitable primary amine (acyl-acceptors). In most instances the result of their reaction is the crosslinking of proteins via intra or inter s (γ-glutamyl)lysine isodipeptide bridges if the primary amine is theε-amino group of the peptide-bound lysine. This leads to increased protein stability and improve protein functional feature. Since wool fibers mainly consist of proteins, transglutaminase can be used to modify the properties of wool keratin. In order to control the damage of wool from anti-felting finishing with protease, the remediation effect of transglutaminase to the damage of wool was studied in this paper. The wool knitted fabrics could reach machine washability standard and the bursting strength loss was controlled by the use of the combination of low temperature, protease and transglutaminase, which was a clean finishing technology.The functional finishing catalyzed cross-linking by transglutaminase was investigated and a new idea was provided for textile functional finishing of energy saving and environmental protection.The dyeing performance of the wool treated with transglutaminase was discussed and the results suggested that the colour depth of dyed wool fabrics could become deeper by use of transglutaminase as color protection and deep reagent. Adsorption of transglutaminase on wool and its catalyzing cross-linking mechanism were researched, which was helpful for the reasonable application of transglutaminase on modification of protein fibers.(1) In this paper, the remediation modification of transglutaminase to the wool was studied. It was shown that transglutaminase can remediate the damage following chemical, protease, chemical/protease combination, and remediation effect of transglutaminase to damage from chemical/protease combination was more obviously. The influences of some factors on the effect of remediation were discussed, including the dosage of transglutaminase, temperature, time and pH value.Through single factor experiments, the better conditions in treating wool yarns with transglutaminase were as followings:dosage of transglutaminase 4%(o.w.f.), temperature 38-42℃,time 2h, pH 6.5-7.0.The optimal conditions in treating wool fabrics with transglutaminase were dosage of transglutaminase 32.45%(o.w.f.) and time 108min. According to these optimum conditions, the strength of fabric treated recovered by 30%. The percentage of area shrinkage and strength of woven or knitted fabric treated with protease were decreased obviously. Transglutaminase not only remediated the damage of wool and increase strength but also decreased the percentage of area shrinkage properly. By the use of bi-anti-felting finishing with lipase, protease and transglutaminase combination, the percentages of area shrinkage of wool woven fabric and knitted fabric decreased to below 3% and about 8% respectively, and the strength values decreased by 10% and 15% respectively. The knitted fabric reached the machine washability standard and the bursting strength was controlled by the modification with low temperature plasma, protease and transglutaminase combination. The result of DTA suggested the thermal degradation temperature of wool treated with transglutaminase raised and thermal stability improved obviously.(2) Transglutaminase was applied to catalyse an acyl transfer between peptide-bound y-glutamyl in wool protein and a suitable primary amine in chitson, silk fibroin, silk sericin, O-Phosphorylethanolamine. In this paper, we investigated the transglutaminase mediated grafting of some functional primary amine on the surface of wool and the functional finishing catalyzed by transglutaminase.It was shown that treatment of wool fabrics with transglutaminase in combination with chitson, silk fibroin, silk sericin led to a significant effect on the properties of wool fabric, such as increased tensile strength, as well as reduced levels of felting shrinkage and improved crease-resistant and antimicrobial performances. Modification of wool fabrics with transglutaminase in combination with O-Phosphorylethanolamine resulted in the content of P in wool increase and that of P in the treating solution decrease, limited oxygen index (LOI) increased to 29. The result of DTA shown the temperature and area of exothermic peak decrease, which suggested that the decomposition of the residues were prevented. DTA also shown the thermal degradation temperature of wool treated with transglutaminase raised and thermal stability improved, which indicated that thermal degradation of wool fiber was delayed and flammable gases were inhibited.(3) The dyeing behavior of the wool treated with transglutaminse was studied.The influences of transglutaminse on the absorption spectrum of weak acid dyes and natural dye were analyzed, including Polar Brilliant Red B, Polar yellow GN, Polar blue RAWL and natural pigment sappan.lt was shown that transglutaminse had no influence on the maximum absorption wavelength of these dyes in visible region, but the corresponding absorbance values at the maximum absorption wavelength increased as the concentration of transglutaminase increased, which revealed that transglutaminase made these dyes deep color and there might be some interaction between transglutaminase and these dyes. The influences of modification with transglutaminase on wool dyeing kinetic and thermordynamic properties with Polar Brilliant Red B were discussed. The results shown that the modification with transglutaminase improved the dyeing rate and the diffusion coefficient, shorten the half-dyeing-time, made the activation energy decrease, and the wool modified by protease and transglutaminase might be dyed at low temperature. The adsorption models of Polar Brilliant Red B on the wool treated or untreated were described by the Langmuir isotherm. Modification of wool with transglutaminase had almost no influence on the dye standard affinity.The adsorption of Polar Brilliant Red B on the wool, either treated or untreated, were spontaneous and reversible exothermic process. The modification of wool with transglutaminase decreased the heat of dye sorption. The standard entropy decreased, either treated or untreated, but the sample treated with transglutaminase had a lowerΔS°than untreated one. Modification of wool with transglutaminase enhanced K/S value of wool dyed subsequently with weak acid dyes and sappan, including direct and after-mordant dyeing with tannic acid, Ferroys sulfate and Alum, and had almost no influence on dyeing fastness. The absorbances of washing liquor at theλmax of three kinds of weak acid dyes were analyzed. The results shown that the amount of dyes released from dyed wool fabrics treated with transglutaminase were lower than those untreated after washing with biological detergent and non-biological detergent. Transglutaminase modification improved the resistance to detergent damage and was effective to maintain colour of dyed wool fabrics after washing biological.and non-biological washing..By analyzing colour parameters of dyed fabrics, it was suggested that transglutaminase, as color protection and deep reagent, could make the colour depth of the dyed wool fabrics deeper.(4) Enzymatic characterization and adsorption, as well as catalyzing cross-linking mechanism of transglutaminase, were studied in this paper. The results shown that the proper pH and temperature of transglutaminase were 6-7 and 45℃respectively, stability scales of transglutaminase were pH6-8 and temperature below 50℃. Ca2+、Mg2+、Ba2+、Fe3+、Mn2+,、K+ and Na+ had little influence on the activity and even had some active effect. The activity of transglutaminase was inhibitated significantly by Cu2+、Zn2+、Hg2+、Pb2+。The transfer reaction of transglutaminase catalyzing wool protein was mutiphase between solid and liquor, the accessibility of transglutaminase to wool fiber was a key factor. The performance of adsorption of transglutaminase on wool substrate was discussed by colorimetry method. The results shown the adsorption of transglutaminase on wool increased with the dosage of transglutaminase, treating temperature and acidity or alkaline increase and the liquor ratio decrease. A normal shaker bath and a ultrasonic bath improved the adsorption of transglutaminase on wool. Pretreatment, especially low temperature plasma, enhance the adsorption. Hydrolysis of wool protein was used as the substrate, the characterization of transglutaminase catalyzing cross-linking was studied by flow time, uv-spectrum and gel electrophoresis. Some performances of wool treated and untreated were analyzed., including acid absorption values, alkali solubility, FTIR reflection absorbance spectra, thermal behaviour, composition and content of amino acid, UV spectra curve of the protein in the intercellular cements and the amount of ammonia NH3 released from reaction solution. It was shown that the flow time of hydrolysis of wool protein increased. The UV spectra curve suggested the amount of amide bonds in hydrolysis of wool protein increased. Gel electrophoresis shown hydrolysis protein macropolymermolecules were so large that they were unable to penetrate the stacking or the separation in SDS-PAGE, and indicated macrpopolymer of hydrolyzed protein of wool formed by transglutaminase catalyzation. Acid absorption values and alkali solubility of the wool treated by transgkutaminase decrease. The analyzation of composition and content of amino acid shown the total of glutamine and glutamic acid in wool accounts for 13.45%(w/w), the total of lysine residues in wool accounts for 2.85%(w/w). Modification of wool with transglutaminase resulted decrease in content of amino acids in wool. The amount of ammonia NH3 released from reaction solution residue increased as the treating time of transglutaminase increased. The SEM shown that the scale structure became more smooth after treating with transglutaminase. The thermogravimery analyzation shown the thermal degradation temperatures of the wool, including untreate,treated with protease and treated with protease-transglutaminase, were 319℃,307.6℃and 317.8℃respectively, the weightlessness at 400℃were 65.4%,65.51% and 62.97%. The thermal behaviour reveled that the thermal stability of the wool treated with transglutaminase enhanced. FTIR reflection absorbance spectra and second derivative spectra of wool treated with transglutaminase shown the amide I and amideⅡabsorbances increase. Uv-spectrum analysis suggested a decrease in protein extracted from the intercellular cements of the wool treated with transglutaminase. The x-diffraction curves of wool treated with transglutaminase were similar to those of untreated and the crystallization index of wool treated with transglutamine increased little. Evidence is therefore provided that wool keratin substrates in the solid state can be self-cross-linked and chemical stability improved.