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羊毛表面生物酶改性及机制研究

Enzymatic Modification of Wool Surface and Its Mechanism

【作者】 王平

【导师】 范雪荣;

【作者基本信息】 江南大学 , 纺织工程, 2010, 博士

【摘要】 传统羊毛防毡缩加工多采用氯化—树脂法,加工中产生的可吸收有机卤化物(AOX)毒性高,环境污染大。本文首先在反胶束体系和水相体系中,应用重组T. fusca角质酶对羊毛织物进行预处理;比较了Savinase蛋白酶与木瓜蛋白酶在羊毛防毡缩整理效果上的差异;考察了Bacillus subtilis菌产角蛋白酶、脂肪酶L3126和Lipex 100L预处理对羊毛蛋白酶改性加工的影响。在低浓度H2O2氧化预处理的基础上,结合角质酶、蛋白酶处理,对羊毛表面酶法改性效果与机理进行了研究。主要研究结果如下:1.考察了反胶束体系中表面活性剂、角质酶浓度与含水量对羊毛后续蛋白酶加工的影响。结果表明,当角质酶浓度为2%(o.w.f),环己烷、正丁醇与Tween-80体积比为5:1:1,含水量(水与Tween-80摩尔比)为25时,角质酶/蛋白酶处理后羊毛织物润湿性改善,纤维表面Allw?rden反应特征减弱。角质酶反胶束体系预处理对羊毛蛋白酶加工有促进作用,处理后羊毛失重率增加,碱溶解度仅蛋白酶处理样相当。仅角质酶反胶束体系处理,羊毛表面类脂去除程度有限,织物表面接触角大于氢氧化钾/甲醇处理样。在角质酶反胶束体系处理中,受含水量、表面活性剂与角质酶浓度、纤维表面可及度等因素影响,羊毛角质酶处理效果有待提高。2.在水相体系角质酶预处理的基础上,比较了不同蛋白酶对羊毛织物的整理效果。羊毛经水相体系角质酶预处理,润湿性好于角质酶反胶束体系处理样,进一步结合蛋白酶处理,润湿性明显改善。羊毛蛋白酶处理中,Savinase蛋白酶(丝氨酸蛋白酶)较木瓜蛋白酶(巯基蛋白酶)具有更高的酶解效率,相同酶浓度条件下Savinase处理样失重率较高。角质酶预处理对Savinase蛋白酶处理有明显促进作用,处理后织物强力与角质酶/木瓜蛋白酶处理样相当,织物水洗后的毡缩率较低。仅Savinase蛋白酶处理,羊毛毡缩性改善较少,原因是Savinase蛋白酶对纤维鳞片角蛋白水解效率较低。3.研究了脂肪酶、角蛋白酶与角质酶组合预处理对羊毛蛋白酶加工的影响。(1)脂肪酶预处理对羊毛织物润湿性与后续蛋白酶加工影响较小,试样失重率与水洗毡缩率变化不明显。(2)单一角蛋白酶处理对鳞片作用效果较小,羊毛织物润湿性改善较少,水洗毡缩率与原样相当;角蛋白酶/蛋白酶处理后,羊毛润湿性、失重率较仅蛋白酶处理样增加,织物毡缩率有所下降,但不及角质酶/蛋白酶处理样。(3)角质酶、角蛋白酶和蛋白酶组合处理进一步改善了羊毛织物表面的润湿性,试样水洗后的毡缩率低于角质酶/蛋白酶和角蛋白酶/蛋白酶处理样。羊毛经角质酶/角蛋白酶/蛋白酶处理后,酶解残液中半胱氨酸含量高于角质酶/蛋白酶处理残液,原因可能与角蛋白酶对羊毛纤维中胱氨酸二硫键有水解作用相关。4.考察了H2O2氧化预处理对羊毛蛋白酶加工的影响。单独H2O2处理对羊毛纤维表面类脂物结构没有明显影响,织物表面润湿性改善较少,试样失重率较低,羊毛防毡缩性能较原样下降。随着H2O2浓度增加,H2O2/蛋白酶组合处理后羊毛织物失重率增加,断裂强力明显下降,但防毡缩性能提高较少,这可能与蛋白酶处理中高深度、低广度的酶解模式相关。H2O2/蛋白酶处理中,羊毛纤维鳞片细胞间质和皮质层蛋白水解较多,鳞片去除以剥离方式为主,羊毛失重率与防毡缩性能之间的相关性不强,防毡缩整理效果不理想。5.考察了低浓度H2O2、角质酶组合预处理对羊毛蛋白酶加工的影响。H2O2弱氧化、角质酶和蛋白酶组合处理后,羊毛表面润湿性明显改善,失重率增加,织物水洗后的毡缩率下降,纤维表面Allw?rden反应特征减弱。2 g/L H2O2 (30%)、4%(o.w.f)角质酶和2%(o.w.f) Savinase蛋白酶处理后,羊毛织物3次水洗后的毡缩率降低至3~5%,强力保留率约为84%,优于角质酶/蛋白酶或H2O2 /蛋白酶处理样,试样染色性能与弹性回复能力、柔软度等织物风格也有明显改善。低浓度H2O2预处理增加了角质酶对羊毛纤维表面类脂的作用效果,使得蛋白酶处理中纤维鳞片角蛋白的水解效率增加,纤维损伤低于H2O2 /蛋白酶处理样。弱氧化、角质酶和蛋白酶组合处理中,羊毛鳞片去除以水解模式为主,试样表面的润湿性与防毡缩性之间存在较好的正相关性,即润湿性越好,织物水洗后的毡缩率越低;失重率与防毡缩性之间的相关性也较H2O2/蛋白酶处理样显著。6.研究了角质酶、角蛋白酶、氧化预处理与蛋白酶处理对羊毛纤维结构组成与外观形态的影响。角质酶处理后羊毛红外光谱特征吸收峰与原样没有明显变化,饱和脂肪酸酯C=O特征吸收峰的强度降低,C元素含量与C/N比下降,表明羊毛纤维表面类脂物得到去除。H2O2处理后羊毛纤维中胱氨酸氧化产物磺基丙氨酸含量增加,类脂物去除效果较差。2 g/L H2O2(30%)与角质酶组合处理后,羊毛纤维表面C元素含量明显下降,O/C比增加,表明纤维表面极性基团数量增多,类脂物去除效果增加。弱氧化、角质酶和蛋白酶三步处理后,羊毛纤维中胱氨酸相对含量较低,SEM验证了羊毛纤维鳞片得到均匀去除。

【Abstract】 As a conventional shrink-proofing process, chlorine-resin treatment endows wool fabric with satisfactory anti-felting ability. However, it has the disadvantage of environmental pollution caused by the toxic adsorbable organic halogen compounds (AOX). In this study, a cutinase from the recombinant Thermobifida fusca was applied to treat wool in the reversed micelles (RS) and aqueous solutions. The differences of shrink-proofing efficacy between Savinase and papain treatments were evaluated. A keratinase from Bacillus subtilis and two lipases of L3126 and Lipex 100L were applied in the wool processing, respectively. The effects of keratinase and lipase pretreatments on the succeeding protease treatment were investigated. Furthermore, the efficacy and mechanism of the combined enzymatic process, based on mild oxidation, cutinase and protease treatments were also concerned. The main conclusions were listed as follows.1. The effects of surfactant, cutinase concentration and the mol ratio of H2O to Tween-80 in RS on the efficacy of succeeding protease treatment were investigated. The results indicated that the protease-treated wool presented improved wettability when pretreated with 2 %(o.w.f) cutinase in RS as follows: the V (cyclohexane):V (alcohol):V (Tween-80) of 5:1:1, mol ratio of 25. The characteristic of Allw?rden reaction for the treated wool became weak. Cutinase pretreatment in RS facilitated the succeeding protease treatment. The combined process endowed wool fabric with a bit higher weight loss without more noticeable increase of alkaline solubility as compared to that of the individual protease treatment. Furthermore, the wettability for the wool treated with cutinase in RS was inferior to that incubated with potassium hydroxide and methanol, the achieved contact angle was still large, which indicated that the removal of the outmost lipids from the wool surface was not completely. The whole efficacy of cutinase treatment in RS was related to the composition of organic solvent and surfactant, the mol ratio of H2O to Tween-80, the concentration of cutinase as well as the accessibility of enzyme to the fatty acids in wool surface. The efficacy of cutinase treatment in RS was to be further improved.2. The effects of cutinase pretreatment in aqueous solution on the shrink-proofing efficacy of protease treatment were discussed. The actions of two proteases during enzymatic wool processing were compared. The results indicated that wettability of the wool treated with cutinase in aqueous solution was better that treated in RS. More acceptable wool wettability was obtained after the combined use of cutinase and protease treatments. The protease of Savinase (a serine protease) showed higher ability to degrade wool protein during enzymatic processing when compared to papain (a cysteine protease), resulting in more weight loss when the concentrations of the two proteases were similar. Cutinase pretreatment efficiently promoted the Savinase treatment, the obtained anti-felting ability of wool was better than that of the sample based on cutinase-papain treatment although the tensile strengths were at the same level. Individual Savinase treatment led to less improvement of anti-felting ability, which was due to the inefficient enzymatic degradation of wool scales during enzymatic processing.3. The effects of the combined use of lipase, keratinase and cutinase pretreatments on the succeeding protease treatment were investigated. (1) Individual lipase treatment did less impact to the wettability of wool as well as to the efficacy of succeeding protease treatment. No obvious changes of weight loss and shrinkage percentage were observed with and without lipase treatment. (2) Keratinase treatment alone seeming did not affect the wool scales; no noticeable improvements of wettability and anti-felting ability were detected after the enzymatic processing. Cutinase-keratinase pretreatment promoted the succeeding protease treatment; it led to more weight loss and less area shrinkage when compared to that of the individual protease treatment. However, the obtained properties of wool did not exceed that based on cutinase-protease treatment. (3) The combination use of cutinase, keratinase and protease treatments endowed wool fabric with better wettability; the obtained area shrinkage after washing cycles was also lower than that with cutinase-protease and keratinase-protease processes. The data from the amino acid analysis of the residual protease-incubated solution indicated that the relative mass concentration of cysteine in cutinase-keratinase-protease treated bath was a bit higher than that of the cutinase-protease treated, which was probably due to the more reduction of disulphide cross-links in cuticle scales by keratinase.4. The effects of the peroxide pretreatment on the succeeding protease treatment were investigated. Individual oxidation did less impact on the outmost lipids in wool surface, no obvious changes of wettability and weight loss were observed after wool processing. The anti-felting ability of wool decreased after individual peroxide treatment when compared to the untreated one. Higher concentrations of peroxide led to more weight loss as well as some strength loss after succeeding protease treatment. However, the anti-felting ability of wool did not further improved, which can be due to the mechanism of the peroxide-protease treatment, i.e. the proteolytic reactions proceeded deeply in the fiber interior instead of evenly in wool surface. When the wool fabric sample was pretreated with high concentration of peroxide, the enzymatic degradation with protease occurred efficiently in the fiber interior, resulting in more degradation of cell memberane complex and cortex protein. For the wool based on peroxide-protease combined treatment, there was no definite correlation between weight loss and anti-felting ability of wool, thus the shrink-proofing property of wool was unsatisfactory.5. The effects of the combined use of mild oxidation and cutinase pretreatments on the succeeding protease treatment were investigated. After the wool fabric sample was combinedly treated with mild oxidation, cutinase and protease treatments, wettability and weight loss of wool increased, low area shrinkage percentage and very weak Allw?rden’s effect were obtained. When the wool fabric was respectively treated with 2 g/L of peroxide (30%), 4% (o.w.f) cutinase and 2% (o.w.f) Savinase protease, the area shrinkage decreased to approximately 3~5 % after three washing cycles, the residual strength percentage was nearly 84%, which was much acceptable as compared to the wool treated with protease alone. The dyeability as well as the fabric styles (including elastic resilience, softness etc), for the combined treated wool, were also better than that based on individual protease treatment. Mild oxidation with low concentration of peroxide promoted the succeeding cutinase treatment and led to more removal of the lipids from the wool epicuticle, making the enzymatic degradation proceed efficiently from the cuticle cells. The obtained fiber damages of wool were lower than that treated with peroxide-protease. For the wool fabric combinedly treated with mild oxidation, cutinase and protease treatments, direct correlation between wettability and anti-felting ability was detected, i.e., better wettabiltiy of wool could lead to lower area shrinkage. Furthermore, the correlation between weight loss and anti-felting ability of wool was also more noticeable than that based on peroxide-protease treatment.7. The effects of cutinase, keratinase, oxidation pretreatments as well as the protease treatment on the structure and composition of wool fibers were analyzed. The FT IR spectra of wool based on cutinase pretreatments did not obviously change when compared to the untreated one. For the wool treated with cutinase, the characteristic peaks of the ester- bond (C=O) became weak, the relative mass concentration of carbon as well as the atomic ratio of carbon to nitrogen decreased, indicating that the lipids content in wool surface might decrease during cutinase pretreatment. For the wool treated with peroxide, the concentration of Cys-SO3H and the atomic ratio oxygen to carbon both increased after peroxide treatment. For the wool treated with 2 g/L of peroxide (30%), cutinase and protease, respectively, the relative mass concentration of carbon decreased, while the atomic ratio of oxygen to carbon increased, revealing that the lipids content in wool epicuticle might decrease and more polar groups exposed on the wool surface. The data from amino acid analysis of wool indicated that the relative mass concentration of cysteine for the cutinase-keratinase-protease treated wool was very low. SEM images verified that the combined use of mild oxidation and cutinase8. pretreatments could evenly increase the extent of scale removal during protease treatment.

  • 【网络出版投稿人】 江南大学
  • 【网络出版年期】2011年 06期
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