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Enzyme and Microbial Technology 44 (2009) 302–308

Contents lists available at ScienceDirect

Enzyme and Microbial Technology

journa l homepage: www.e lsev ier .com/ locate /emt

ffects of cutinase on the enzymatic shrink-resist finishing of wool fabrics

ing Wanga, Qiang Wanga, Xuerong Fana,∗, Li Cuia, Jiugang Yuana, Sheng Chenb, Jing Wub

Key Laboratory of Science and Technology of Eco-Textiles, Ministry of Education, Jiangnan University, Wuxi 214122, ChinaSchool of Biotechnology, Jiangnan University, Wuxi 214122, China

r t i c l e i n f o

rticle history:eceived 22 September 2008eceived in revised form 22 January 2009ccepted 26 January 2009

a b s t r a c t

A novel microbial cutinase from Thermobifida fusca WSH04 was applied in the pretreatment of woolfabrics followed by protease treatment, aiming at improving the wettability of the samples by hydrolyzingthe outmost bound lipids in the wool surface. Cutinase pretreatment could increase the efficacy of thesubsequent protease treatment by improving the wettability, dyeability, and shrink-resistance of the

eywords:ool

ipidsutinaseroteaseydrogen peroxide

wool fabrics. The data obtained by the XPS method showed the changes of elemental concentration inthe wool surface after cutinase pretreatment. Compared with the fabrics treated with hydrogen peroxideand protease, the combination of cutinase and protease treatments produced better results in terms ofwettability and shrink-resistance with less strength loss. The anti-felting property of the fabrics treatedwith the enzymatic resist-shrink technique is very promising to meet the commercial standard.

© 2009 Elsevier Inc. All rights reserved.

hrink-resist finishing

. Introduction

The treatment of wool fabrics with protease, an environmentallyriendly technique, has been intensively explored as an alternativef the commercial chlorine-Hercosett process to provide shrink-esist property to wool fabrics [1]. The cuticle membrane in theool surface is mainly composed of naturally occurring lipids

onnecting cysteine residues via thioester or ester bonds and cova-ently crosslinked isopeptide via amide bonds, which makes the

ool surface highly hydrophobic and the enzymatic degradationo the cuticle cells restrictedly. Some native proteases can pene-rate through the intercellular cement and cause unacceptable fiberamages [2–4]. Chemical or physical treatments, such as alkali, oxi-ation, chlorination, or plasma treatments, can dislodge some fattycids bonds in the wool surface, break some disulphide crosslinksnd provide polar functional groups. These pretreatments mightelp the accessibility of the enzyme to wool substrate duringhe following protease treatment [5,6]. However, some chemicalretreatments have the disadvantages of causing excessive fiberamages and uneven treatments of wool surface.

Enzymes, such as lipases and the chemically modified pro-

eases, have the great potential application in wool processingithout causing significant damage to wool fibers. The enzymaticrocess based on the chemically modified proteases has been inves-igated by several groups [7–9]; a satisfactory anti-felting effect was

∗ Corresponding author. Fax: +86 510 85912007.E-mail address: wxfxr@163.com (X. Fan).

141-0229/$ – see front matter © 2009 Elsevier Inc. All rights reserved.oi:10.1016/j.enzmictec.2009.01.007

achieved without any significant weight loss. Lipases are expectedto remove the hydrophobic complexes and long chain fatty acids inthe wool surface, which might promote the succeeding proteolyticreactions. Several papers have addressed the treatment of woolfibers with lipase since 1991. El-Sayed et al. [10] reported that thelipase pretreatment in the shrink-resist process of wool fabric couldhelp to improve the wettability of the fibers and enhance shrink-resistance about 2–3%. Hutchinson et al. [11] studied the activities ofthioesterase and several lipases with the thioester substrate mimic.Although the conversion of the substrate reached 90% under theoptimal condition, there was no observable change in the wetta-bility of the wool fabric. Monlleó et al. [12] also published a paperabout the lipases treatment of wool fibers, and they found that noneof the commercial lipases changes the surface of wool significantlyby using microscopic examination and wettability test. Thus, theefficacy of lipases in wool processing is still argumentative.

Cutinases display hydrolytic activity towards a broad variety ofaliphatic esters [13–15]. Eberl et al. [16] reported that the treatmentof poly(trimethylene terephthalate) (PTT) fabrics with cutinaseimproved the dyeability with a significant increase in K/S value.More recently, Agrawal et al. [17] demonstrated that cutinase treat-ment enhanced the degradation of cotton waxes and increased thehydrolytic rate of pectinase during cotton scouring. Since the out-most bound lipids in the wool surface are a complex mixture of

aliphatic lipids, cutinase might have the potential application inthe pretreatment of wool fibers. The major objective of this study isto investigate the application of cutinase in the wool bioanti-feltingfinishing to improve the wettability and shrink-resistance of woolfabrics.

P. Wang et al. / Enzyme and Microbial Technology 44 (2009) 302–308 303

Table 1Wettability of wool fabrics treated with cutinase and protease.

Samples Wetting (time/min) Contact angle (◦)

a b a b

Control (pretreated without cutinase) >30 18.5 134.83 123.15Control (pretreated with deactivated cutinase) >30 17.2 126.18 106.32PP

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retreated with cutinase 7.9retreated with H2O2 21.2

: no protease treatment; b: protease-treated.

. Materials and methods

.1. Materials

Cutinase was produced from a mutant Thermobifida fusca WSH04 according tohe method described previously by Du et al. [18]. The activity of cutinase was deter-

ined by a continuous spectrophotometric assay utilizing p-nitrophenylbutyratepNPB) as the substrate. The standard assay was measured in a final volume of 1 mlontaining pNPB (1 mM), enzyme, and the assay buffer (pH 8.0) at 20 ◦C. The reactionas initiated by the addition of pNPB. The hydrolysis of pNPB was spectrophotomet-

ically monitored for the formation of p-nitrophenol (pNP) at 405 nm. The measuredctivity of cutinase was about 300 U/mL. One unit of enzyme activity is defined ashe production of 1 �mol pNP per minute.

Protease of Savinase 16 L was supplied by Novozymes A/S, China. The activityf Savinase was determined, according to Silva et al. [19] utilizing casein as sub-trate. The formation volume of tyrosine derived from hydrolyzed casein was assayedy way of colorimetry using the Folin & Ciocalteu’s reagent. The measured activityf protease was about 20,000 U/mL. One unit of enzyme activity is defined as theroduction of 1 �mol tyrosine per minute at pH 7.5 and 40 ◦C.

Worsted wool fabric (Gaberdine, 100% pure, 410 ends/10 cm × 250 picks/10 cm)as supplied by Wuxi Xiexin Group, China. Wool fabrics were cleaned by Soxhlet

xtraction with chloroform/methanol 87:13 (v/v) at 65 ◦C for 8 h, six extrac-ion cycles per hour were used. This cleaning method ensured the removalf all free internal lipids and other contaminants from the fiber surface. Allhemicals used in this work were purchased from Sinopharm Chemical Reagento., Ltd., China.

.2. Treatment methods

.2.1. Pretreatments of wool fabrics with cutinase or hydrogen peroxideCutinase and peroxide pretreatments were applied to remove the bound fatty

cids in the wool surface, respectively. The fabric samples were incubated in cutinaseolution (10 U/g fabric) at pH 8.0 and 60 ◦C for 4 h with a liquor ratio of 25:1, theninsed with cold water and dried at room temperature. For comparison, the controlamples were incubated in the same condition without cutinase or with deactivatedutinase. In addition, peroxide pretreatment as a contrastive method was carriedut with 20 g/L hydrogen peroxide at pH 9.0 and 50 ◦C for 1 h. All the above treatedamples were extracted again to remove the cleaved fatty acids that might have beenbsorbed by the wool fibers.

.2.2. Protease treatment of wool fabricsThe wool fabrics were treated with protease (approximately 250 U/g fabric) at

H 8.5 and 55 ◦C for 1 h. The liquor ratio of the solution is 25:1. The protease-treatedool fabrics were dipped in boiling water for 2 min to deactivate the enzyme, washed

horoughly and then air-dried.

.3. Testing procedure

.3.1. WettabilityThe wettability of wool fabric was characterized by using the wetting time (in

in) and contact angle. The wetting time of wool samples was determined accordingo the drop test (AATCC Test Method 39-1980). Contact angle of each sample was

easured with the Drop Shape Analysis System DSA 100 (Olympus, Japan). Thisethod used distilled water with a drop size of 0.02 mL as test liquid. Data of contact

ngle were recorded after 10 s of contact. Ten measurements were taken on theifferent places of the fabrics.

.3.2. Weight lossThe average weight loss percentage (WL%) of each sample was calculated by

ollowing equation:

L (%) = 100 × A − B

A

here A is the weight of the untreated wool fabric, and B is the weight of the woolabric after pretreatment or combination treatments. All samples were balanced at5 ◦C and RH 60% for 24 h before testing.

1.3 92.04 66.8211.5 127.33 98.14

2.3.3. Tensile strengthThe tensile strength of wool fabric was measured by a YG(B) 026D-250 fabric

tensile strength tester (Darong Textile Instrument Company, China) according to themethod of ISO 5081. The results of tensile strength expressed as maximum load inthe warp direction were given as the arithmetic means of three different samples.

2.3.4. Alkaline solubilityThe alkaline solubility of wool fabric refers to the percentage of weight loss of

wool fibers in alkaline solution. It was determined according to the method of IWTO4-60 and the results were given as the arithmetic means of three parallel samples.

2.3.5. Felting shrinkageThe shrinkage of wool fabric was measured according to IWS Test Method 31.

Prior to any treatments, wool fabrics were subjected to a 7A program for relaxationshrinkage in a Y(B)089A washing machine (Darong Textile Instrument Company,China). Felting area shrinkage tests were conducted with 5A program. The resultswere expressed as the percentage of area shrinkage after relaxation and given as thearithmetic means of three parallel runs.

2.3.6. Dyeing and K/S measurementThe dyeing was initiated with 0.02 g/L Acid Blue 80 (Wande Dyestuff Company,

China) at pH 5.5 and 40 ◦C in a laboratory dyeing machine (Rapid, Taiwan). The liquorratio of dye bath is 50:1. After the temperature of dye bath was raised to 90 ◦C over15 min, the dyeing was kept at 90 ◦C for 45 min. Finally, the wool fabrics were rinsedtwice with distilled water and air-dried. The K/S values were determined accordingto the Kubelka–Munk equation at the wavelength of 628 nm, which is the wave-length of maximum dye absorption, by using a Color-Eye 7000A spectrophotometer(GretagMacbeth, USA).

2.3.7. FT-IR ATRA Thermo Nicolet Nexus FT-IR spectrophotometer (Thermo Electron Corpora-

tion, USA) was used to record the changes of the characteristic groups on the surfaceof wool, as described by Wang et al. [20].

2.3.8. XPS characterizationX-ray photoelectron spectroscopic (XPS) experiments were carried out to mon-

itor the changes produced in the outermost layer of the wool surface, usinga RBD upgraded PHI-5000C ESCA system (PerkinElmer) with Mg K� radiation(h� = 1253.6 eV) or Al K� radiation (h� = 1486.6 eV). The X-ray anode was run at250 W and the high voltage was kept at 14.0 kV with a detection angle at 54◦ . The passenergy was fixed at 23.5, 46.95 or 93.90 eV to ensure sufficient resolution and sensi-tivity. The base pressure of the analyzer chamber was about 5 × 10−8 Pa. The samplewas directly pressed to a self-supported disk (10 mm × 10 mm) and mounted on asample holder then transferred into the analyzer chamber. The spectra of all theelements with much high resolution were both recorded by using RBD 147 interface(RBD Enterprises, USA) through the AugerScan 3.21 software. Binding energies werecalibrated by using the containment carbon (C1s = 284.6 eV). The data analysis wascarried out by using the RBD AugerScan 3.21 software provided by RBD Enterprises.

2.3.9. Scanning electron microscopy (SEM)The surface morphologies of wool samples were characterized by a FEI Quanta-

200 scanning electron microscope (FEI Company, The Netherlands). Samples weresputter-coated with gold before scanning.

3. Results and discussion

3.1. Effects of cutinase pretreatment on wettability ofprotease-treated wool fabrics

Enzymatic or chemical treatments can partially destroy orremove the covalently bound fatty layer in the surface of wool fibersthat causes wool fiber hydrophobic. Table 1 shows the effects ofcutinase and peroxide pretreatments on the wettability of woolfabrics in terms of wetting time and contact angle. The cutinase

304 P. Wang et al. / Enzyme and Microbial Technology 44 (2009) 302–308

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small protease molecules penetrate into overlapping cuticle cellsand hydrolyze the proteins in the cortex cells and cell membranecomplex, which also slightly increased the fiber damages.

By contrast, the application of hydrogen peroxide in combina-tion with protease treatment had a severe impact on the integrity of

ig. 1. Weight loss of wool fabrics after protease treatments. (a) Control; (b) pre-reated with cutinase; (c) pretreated with hydrogen peroxide.

retreatment had a dramatic effect on the wettability of wool fibersy hydrolysis of the hydrophobic outer layer, the wetting time andontact angle reduced to 7.9 min and 92.04◦ after pretreatment.he phenomenon is similar to the previous report by Degani etl. [21] who detected an increase of hydrophilicity of raw cottonabrics by using cutinase. Unlike the cutinase treatment, the pre-reatment with deactivated cutinase did not obviously change theettability of the wool fabric. In contrast to the excellent wettability

f wool fabric achieved after KOH/methanol treatment [22], cuti-ase treatment alone was unable to reach a complete removal ofhe covalently bound lipids in the fiber surface; there was no moreignificant improvement in wettability observed even after a 24 hutinase pretreatment. This is likely associated with the selectivityf cutinase towards ester- and thioester-bound in wool cuticle, asell as the accessibility of cutinase active sites toward the outmostydrophobic bound lipids in the wool surface. On the other hand,ydrogen peroxide pretreatment could break some cystine disul-hide crosslinkages and increase the amount of polar functionalroups in the wool surface [23]; however, no significant improve-ent of hydrophilicity was observed after the oxidation treatment.The protease molecules not only hydrolyze the cuticle of the

bers but also penetrate into the fibers during wool processing,esulting in the removal of smaller peptide and protein segmentsith an increase of amorphous regions. As shown in Table 1, therotease treatment with or without pretreatment increased theettability of the wool fabrics to different extents. The pretreat-ents could facilitate the accessibility of protease onto the surface

f wool fibers and promote the proteolytic reactions, making morenderlying proteins (hydrophilic surface) exposed to the surface. Itas particularly remarkable for the sample based on cutinase pre-

reatment. The combination of cutinase and protease treatmentsf the wool fabric reduced the wetting time and contact angle to.3 min and 66.82◦, respectively.

.2. Effects of cutinase pretreatment on weight loss, tensiletrength and alkaline solubility of protease-treated wool fabrics

According to the data shown in Fig. 1, cutinase treatment orydrogen peroxide treatment alone did not cause the obviouseight loss of wool fabric, whereas they evidently enhanced the

ctivity of Savinase towards wool in the subsequent protease treat-ent. The weight losses of the fabrics treated with cutinase and

ydrogen peroxide respectively reached to 6.3 and 6.9% after pro-ease treatment, achieving approximately 3% increase of weight losss compared with that of the control. The increase of weigh lossndicated cutinase or hydrogen peroxide pretreatment enhanced

Fig. 2. Tensile strength of wool fabrics before and after protease treatments. (a)Control; (b) pretreated with cutinase; (c) pretreated with hydrogen peroxide.

the succeeding proteolytic reaction, leading to more degradationof the cuticle scales or the interior of wool fibers. Generally, theconsiderable increase in weight loss might accompany with thepotential fiber damages, which could be assessed by means of ten-sile strength and alkaline solubility. For the samples pretreated withcutinase alone, there was no evident difference of tensile strengthor alkaline solubility from that of the control. While pretreated withhydrogen peroxide alone, weigh loss occurred accompanying with aslight decrease of tensile strength (Fig. 2), which might be ascribedto the use of peroxide in an alkali bath. The succeeding proteasetreatment had obvious effect on the tensile strength and alkalinesolubility of the wool fabrics. As shown in Figs. 2 and 3, the decre-ments of tensile strength and the increments of alkaline solubilitydiffer from each other after protease treatments. Among the threesamples, the control fabric achieved the least fiber damages duringprotease treatment. As for the fabric pretreated with cutinase, theeffects of protease treatment on alkaline solubility and strength losswere relatively moderate, which is probably associated with themechanism of enzymatic reactions. Cutinase pretreatment couldpartially dislodge the lipid-rich outer layer in the wool surface andmight favor the adsorption of protease, resulting in more degrada-tion of the underlying proteins during wool processing. Meanwhile,

Fig. 3. Alkaline solubility of wool fabrics before and after protease treatments. (a)Control; (b) pretreated with cutinase; (c) pretreated with hydrogen peroxide.

P. Wang et al. / Enzyme and Microbial Technology 44 (2009) 302–308 305

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whiteness index of the fabric pretreated with hydrogen perox-ide was slightly higher than the other two. Fig. 6 shows the K/Sof the dyed wool fabrics, there are no significant differences ofK/S between the sample treated with cutinase alone and the con-trol fabric after dyeing disregard of the better wettability of the

ig. 4. FT-IR ATR spectra of wool fiber keratin over range 1000–1400 cm−1. (a) Con-rol; (b) pretreated with cutinase; (c) pretreated with hydrogen peroxide.

he fabric; the tensile strength in Fig. 2 decreased nearly 50% afterrotease treatment. The considerable fiber damage was mainlyelative to the peroxide pretreatment prior to the enzymatic incu-ation. Without the presence of high concentrations of salt, theeroxide pretreatment will no longer modify specifically the outerurface protein layer of wool fiber [24], but breaks the disulphideinkages in the underlying layer containing cysteine-rich proteinnd provides higher fiber swelling for protease diffusion into theber, thus the strength loss increased ultimately. The character-

stic peak at 1040 cm−1 of cysteic acid as the oxidation productainly from hydrogen peroxide pretreatment did not appear in the

R spectrum of cutinase-treated wool (Fig. 4). This information fur-her confirmed that cutinase treatment alone had hardly influencen the cystine disulphide crosslinkages as hydrogen peroxide did.

Generally, these fiber damages caused by proteolytic reactionight be decreased by utilizing the chemically modified protease

7,8,25], which is mainly due to the fact that the increase in molecu-ar size of protease makes the enzymatic degradation of wool fiberse limited to the cuticle scales. It has been demonstrated by Shen etl. [7] that the modification of the enzyme does control the reactionf the enzyme with the wool, and in all cases the modified protease-reated wool presented less damage than the native protease. As forutinase treatment in this study, processing of wool fabrics withutinase was capable of removing some of hydrophobic substratesnd exposed a proteinaceous surface. This would enhance the suc-eeding enzymatic degradation of the exposed proteins in theool surface, and simultaneously reduce the preferential attacks

owards the parts of endocuticule, intermacrofibrillar material andhe intercellular cement of wool fiber. Thus, the combination of cuti-ase and protease treatments is also promising in decreasing fiberamage.

.3. Effects of cutinase pretreatment on the shrinkage ofrotease-treated wool fabrics

The percentages of area shrinkage of wool fabrics before andfter protease treatment are plotted in Fig. 5. The area shrink-esistance of the wool fabric treated with cutinase alone was similaro that of the control. On the contrary, the area shrinkage of the woolabric treated with hydrogen peroxide alone increased dramatically,

hich is consistent to the previous reports [26,27]. The diffusing ofuch more water into the underlying layer of wool fibers through

he channels with high content of cysteic acid might account for theig shrinkage of the samples. It would result in an intensive swelling

Fig. 5. Percentages of area shrinkage of wool fabrics before and after proteasetreatment. (a) Control; (b) pretreated with cutinase; (c) pretreated with hydrogenperoxide.

of the fiber surface and an increase in coefficient of friction duringa long-time shrinkage testing.

It can be found in Fig. 5, the shrink-resistance of the wool fab-rics increased to different levels after protease treatment. The areashrinkage of the wool fabric pretreated with cutinase reached toa minimum of 4%, which is a desirable result, mainly due to theimprovement of wettability of wool surface in cutinase pretreat-ment and the succeeding partial removal of cuticle scales duringproteolytic reactions. Accordingly, the combination of cutinase andprotease shrink-resist process is promising in solving the problemof the wool shrink-resist finishing process, which could cause lowarea shrinkage and alkaline solubility, in despite of the differencebetween the shrinkage data of fabric treated with cutinase andprotease and the commercial Woolmark requirement (3%).

3.4. Effects of cutinase pretreatment on dyeability ofprotease-treated wool fabrics

Before enzyme treatment with protease, the K/S values of thecontrol, cutinase-treated and hydrogen peroxide-treated fabricswere 0.15, 0.18 and 0.07, respectively. The K/S of the fabrics beforeprotease treatment were almost at same level, even though the

Fig. 6. K/S values of wool fabrics before and after protease treatment. (a) Control;(b) pretreated with cutinase; (c) pretreated with hydrogen peroxide.

306 P. Wang et al. / Enzyme and Microbial Technology 44 (2009) 302–308

ol; (b)

chwmtcteotecf

3

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S

CPP

Fig. 7. XPS spectra of the wool fibers after pretreatment. (a) Contr

utinase-treated fabric. Whereas the wool fabric pretreated withydrogen peroxide pretreatment showed a lower K/S as comparedith that of the control fabric (Fig. 6). The lower K/S value isainly due to the cysteic acids produced from the cleavage of

he disulphide bonds by the oxidation of hydrogen peroxide. Theysteic acids produced by the pretreatment increased the elec-rostatic repulsion forces between the polar groups of wool andlectronegative dyes in dyeing solution which led to the decreasef K/S value. Samples pretreated with cutinase produced satisfac-ory shade depth after protease treatment mainly because of thenhancement of wettability, the uniform removal of outer cuti-le during protease processing, and also less electrostatic repulsionorces in dyeing bath.

.5. XPS characterization of wool fabrics after pretreatment

The investigation of surface elemental composition of the woolbers after pretreatment was carried out using XPS, which is sen-

able 2lemental analysis (atom conc.%) and atomic ratio of wool fabrics after pretreatment.

amples Elemental concentration (atom conc.%)

C 1s N 1s O 1s

ontrol 76.48 5.74 14.71retreated with cutinase 73.13 9.22 14.24retreated with H2O2 73.42 5.95 17.27

pretreated with cutinase; (c) pretreated with hydrogen peroxide.

sitive to a depth approximately the thickness of the epicuticle [28].The XPS spectra of the wool fibers after pretreatment are shownin Fig. 7, and a quantitative evaluation of the atomic concentra-tions in the wool surface is summarized in Table 2. For the fabricwith cutinase pretreatment alone, the overall carbon concentra-tion decreased for about 3.4% as compared with that of the control,simultaneously with an increase of the concentrations of nitrogen.The observed decrease in the carbon concentrations can be inter-preted as the result of the partial removal of the outmost boundlipids in the wool surface by enzymatic hydrolysis. The change inthe nitrogen concentrations might be attributed to more exposureof underlying protein material located beneath the fatty acid layerafter cutinase treatment. However, the carbon to nitrogen ratio

was 7.9:1, considerably lower than the C:N ratio expected from thepublished amino acid analysis of the epicuticle [29], which wouldbe approximately 3.4:1, suggesting that the outmost bound lipidsremoval may be incomplete after cutinase treatment. In term ofthe results based on hydrogen pretreatment, the change of atom

Atomic ratio

S 2p C/N O/C

2.06 13.32 0.192.55 7.93 0.191.66 12.34 0.24

P. Wang et al. / Enzyme and Microbial

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[13] Silva CJSM, Carneiro F, O’Neill A, Fonseca LP, Cabral JSM, Güebitz G, et al.

ig. 8. SEM images of protease-treated wool fabrics. (a) Control; (b) pretreated withutinase; (c) pretreated with hydrogen peroxide.

oncentrations was some similar to that of the fabric with cutinase

reatment. The remarkable increase of oxygen concentration andigher oxygen to carbon ratio is likely due to some oxidation ofhe underlying protein below the fatty acid layer, i.e. the disulphideonds are oxidized to cysteic acid residues.

[

Technology 44 (2009) 302–308 307

3.6. SEM images of wool fabrics after protease treatmentfollowing pretreatment

The surface morphology of wool samples treated with proteasewas characterized by SEM (Fig. 8). Significant changes could beobserved in terms of the visual surface of the wool fibers afterprotease processing. Protease treatment and the following hydro-gen peroxide treatment caused apparent damage to fibers (Fig. 8c).SEM micrographs also provide the evidence that the cutinase pre-treatment helped the proteolysis of cuticle layers, showing a partialremoval of the scales with smooth edges (Fig. 8b).

4. Conclusion

The wettability of wool fabric was improved after cutinase treat-ment compared with that of the sample pretreated with hydrogenperoxide. The weight loss of the sample treated with cutinase wassimilar to that of the fabric treated with hydrogen peroxide. Theencouraging shrink-resistance and weakened fiber damage werealso achieved after the combination of cutinase and protease treat-ments. The partial dislodgement of the lipid-rich outer layer andthe increase of the wettability caused by the cutinase pretreatmentmake the succeeding proteolysis with protease easily occur fromthe underlying protein layer on wool surface. Using X-ray photo-electron spectroscopy (XPS), a loss of hydrocarbon from the fibersurface was detected after cutinase pretreatment. The combinationof cutinase and protease treatment improved the dyeability of thewool fabrics mainly due to the enhancement of the wettability andthe uniform removal of outer cuticle during the protease treatment.

Acknowledgments

This work was financially supported by the National HighTechnology Research and Development Program of China(2008AA02Z203), Jiangsu Provincial Graduate Innovation Project(CX08B 126Z) and Qing Lan Project.

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