research article the enzymatic decolorization of textile...

Research ArticleThe Enzymatic Decolorization of Textile Dyes bythe Immobilized Polyphenol Oxidase from Quince Leaves

Gulnur Arabaci and Ayse Usluoglu

Department of Chemistry Faculty of Science and Arts Sakarya University Serdivan 54187 Sakarya Turkey

Correspondence should be addressed to Gulnur Arabaci garabacisakaryaedutr

Received 30 August 2013 Accepted 4 November 2013 Published 21 January 2014

Academic Editors Z P Cakar and M Talat

Copyright copy 2014 G Arabaci and A Usluoglu This is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work is properlycited

Water pollution due to release of industrial wastewater has already become a serious problem in almost every industry using dyes tocolor its products In this work polyphenol oxidase enzyme fromquince (CydoniaOblonga) leaves immobilized on calcium alginatebeads was used for the successful and effective decolorization of textile industrial effluent Polyphenol oxidase (PPO) enzymewas extracted from quince (Cydonia Oblonga) leaves and immobilized on calcium alginate beads The kinetic properties of freeand immobilized PPO were determined Quince leaf PPO enzyme stability was increased after immobilization The immobilizedand free enzymes were employed for the decolorization of textile dyes The dye solutions were prepared in the concentration of100mgL in distilled water and incubated with free and immobilized quince (Cydonia Oblonga) leaf PPO for one hourThe percentdecolorization was calculated by taking untreated dye solution Immobilized PPO was significantly more effective in decolorizingthe dyes as compared to free enzyme Our results showed that the immobilized quince leaf PPO enzyme could be efficiently usedfor the removal of synthetic dyes from industrial effluents

1 Introduction

Synthetic dyes are extensively used in many fields of indus-tries for example the textile leather paper rubber plasticscosmetics pharmaceutical and food [1] The effluent of was-tewater from these industries especially textile contains a var-iety of large quantities of dyes which are inert and may betoxic at the concentration discharged into receiving waterMany of these dyes which have complex aromatic molecularstructures are also toxic and even carcinogenic and pose aserious threat to living organisms [2] Toxic effects of indus-trial dyes encouraged researchers to continue studies on che-mical and enzymatic methods to remove such hazardousma-terials [3 4] Compared to physicochemical methods such asprecipitation filtration and absorption the enzymatic treat-ments of dyes have low energy cost and are more ecofriendlyprocess not still commonly used in the textile industries [5]

Unfortunately conventional wastewater treatments areineffectual at removing dyes and involve high cost forma-tion of hazardous by-products and intensive energy require-ments Moreover complete dye removal is unfeasibleThis has impelled research into alternative methods like

biotechnological processes Recently enzymatic approachhas attracted much interest in the removal of phenolic pol-lutants from aqueous solutions [6] Oxidoreductive enzymespolyphenol oxidases and peroxidases are participating inthe degradationremoval of aromatic pollutants from variouscontaminated sites [7 8] Polyphenol oxidases can act on abroad range of substrates such as substituted polyphenolsaromatic amines benzenethiols and a series of other easilyoxidizable compounds Thus they can catalyze the decol-orization and decontamination of organic pollutants In viewof the potential of the enzymes in treating the phenolic com-pounds several microbial and plant oxidoreductases havebeen employed for the treatment of dyes but none of themhas been exploited at large scale due to low enzymatic activityin biological materials and high cost of enzyme purificationIn order to improve polyphenol oxidases activity and stabilityenzyme immobilization technology has been applied Thistechnology is an effective means to make enzymes reusableand to improve its stability which is considered as a promis-ing method for the effective decolorization of dye effluentsAccording to the previous reports various types of supporterswere applied to immobilize enzyme such as activated carbon

Hindawi Publishing Corporatione Scientific World JournalVolume 2014 Article ID 685975 5 pageshttpdxdoiorg1011552014685975

2 The Scientific World Journal

celite controlled porosity glass chitosan microspheres andalginate [9ndash13]

In this study our first objective was to find a cheaper andeasily available alternative plant polyphenol oxidase (PPO)enzyme source for the commercially available ones and itsimmobilization Quince leaves (Cydonia Oblonga) which arewaste in Turkey have been employed in this work as an easilyavailable and inexpensive PPO enzyme source PPO enzymewas partially purified from quince (Cydonia Oblonga) leavesand immobilized on calcium alginate beadsThe biochemicalproperties were determined for free and immobilized quince(Cydonia Oblonga) leaf PPO The second objective was toevaluate the performance of free and immobilized polyphe-nol oxidases regarding the decolorization of various reactiveacid direct and basic dyestuffs

2 Materials and Methods

21 Materials Quince (Cydonia Oblonga) leaves used in thisstudy were obtained from Sakarya region Turkey and sto-red at ndash20∘C until used Polyvinylpolypyrrolidone (PVP)(NH4)2SO4 Sodium alginate CaCl

2 and other chemicals

were obtained from Sigma Chemical Co and dyes wereprovided by kindly DyStar Huntsman and Yorkshire

22 Extraction and Purification 30 g of quince (Cydonia Obl-onga) leaves was obtained from local Sakarya regionThe leafsamples were added to 50mM sodium phosphate buffer (pH70) 05 g polyvinylpolypyrrolidone (PVPP) and 10mMascorbic acid and themixturewas homogenizedwith blenderAfter the filtrate was centrifuged at 14000 g for 30min thesupernatant was collected Extraction was fractionated with(NH4)2SO4 solid (NH

4)2SO4was added to the supernatant

to obtain 80 saturation The mixture was centrifuged at14000 g for 30 minutes and the precipitate was dissolved ina small amount of phosphate buffer and then dialyzed at 4∘Cin the same buffer for 24 h with three changes of the bufferduring dialysis The dialyzed enzyme extract was collectedand used for all other processes

23 Enzyme Immobilization Alginate solution (1 2 3 wv)was prepared by dissolving sodium alginate in deionized wa-ter Crude quince leaf PPO solution was mixed with 20mL ofalginate solution at the enzymealginate ratio of 1 10 (vv)Themixture was stirred with magnetic stirring to ensure thatcomplete Ca-alginate beadswere produced as soon as the em-ulsion was added into 100mL 3M CaCl

2(1 2 3 wv) The

beads were allowed to harden for at least an hour under mildagitationThen the Ca-alginate beads were removed from theencapsulation medium via centrifugation and rinsed twicewith 05 (wv) CaCl

2containing 1 (vv)

24 PPO Activity Assay The activity of free and immobilizedPPO was determined at room temperature using catechol asa substrateThe assay mixture consisted of 295mL of 20mMcatechol in 005M potassium phosphate buffer pH 70 and005mL of enzymeThe increase in absorbance at 420 nmwasmeasured as a function at time for 1min One unit of enzymeactivity is defined as the amount of the enzyme that causes an

increase in absorbance of 0001 per min at 25∘C PPO activitywas assayed in triplicate measurements

For determining Michaelis constant (119870119898) and maximum

velocity (119881max) values of the enzyme PPO activities weremeasured with catechol at varying concentrations underoptimum conditions of pH and temperature 119870

119898and 119881max

values of PPO for catechol substrate were calculated froma plot of 1119881 against 1[119878] by the method of Lineweaver andBurk [14]

25 Influence of pH The activity assays were carried out overthe pH range 35ndash90 Reaction rates of free and immobilizedenzyme preparations depending on pH were investigatedusing 50mM acetate buffer at pH 35 40 50 and 50mMand phosphate buffer at pH 60 70 75 80 and 90 Activityof pH profiles was determined at various pH values in 10mMcatechol solution at 25∘C

26 Influence of Temperature The effect of temperature onenzyme activity was investigated in the range of 4ndash70∘C forboth free and immobilized PPO enzymes Activity of tem-perature profiles was determined at indicated temperaturesin 10mM catechol solution (pH 70)

27 Effect of pH and Time on the Decolorization of TextileDyes Neutrilan Black MRX (CI Acid Black 194) TelonTurquoise M-5G (CI Direct Blue 86) Lanaset Yellow 4GN(CI ReactiveYellow 39) TelonYellowARB (CI AcidOrange67) Isolan Grey NHFS (CI Acid Black 220) Telon RedMGWN Solophenyl Red 7BE and Astrazon Yellow 7GLL(CI Basic Yellow 21) dyes were selected for this study Eachdye was incubated with soluble and immobilized quince leafPPO 15 EUmL in the buffers of varying pH values 40ndash70 at25∘C Each dye was also incubated with immobilized quinceleaf PPO 15 EUmL in pH 40 at 25∘C for 30ndash60ndash90minDye decolorization by PPO was monitored at the specificwavelength The decolorization percentage was calculated bytaking untreated dye solution as control of each buffer (100)

28 Calculation of Dye Decolorization Rate Startingabsorbance at characteristic max for each dye (control) wasdesignated as 100 The extent of decolorization rate wasdefined by the following formula

Decolorization percentage () =(119860119900minus 119860)

119860119900

times 100 (1)

where 119860119900is the absorbance of the untreated dye and 119860 is the

absorbance after treatment [15]

3 Result and Discussion

31 Effect of pH on Free and Immobilized PPO For thedetermination of the effect of pH on free and immobilizedenzymes by acid phosphate buffers were used within the pHrange of 35ndash90 The optimum pH for free and immobilizedquince leaf PPO was 75 respectively (Figure 1) Both freeand immobilized quince leaf PPO gave similar pH valuesHowever the immobilized leaf PPO gave much broader pH

The Scientific World Journal 3

0

20

40

60

80

100

3 4 5 6 7 8 9pH

Rela

tive a

ctiv

ity (

)

Figure 1 Effect of pH on activity (998771) free PPO and (◼) immobilizedPPO

0

20

40

60

80

100

0 10 20 30 40 50 60 70

Rela

tive a

ctiv

ity (

)

Temperature (∘C)

Figure 2 Effect of temperature on activity (998771) free PPO and (◼)immobilized PPO

stability than the free enzymeThis suggests that immobilizedquince leaf PPOwas less sensitive to pH changes than the freeone

32 Effect of Temperature on Free and Immobilized PPOAt the determination of the effect of temperature on freeand immobilized quince leaf PPO activity was investigatedin phosphate buffer in a temperature range of 4ndash70∘C Theresults showed that the optimum temperatures of the freeand immobilized enzymes were 30∘C and 35∘C respectively(Figure 2) The thermostability of immobilized quince leafPPO enzyme was obviously better than free enzyme Theenhanced thermal stability of enzymes arising from immo-bilization would be an advantage for its industrial applicationdue to the high temperatures used in the industrial processes[16]

33 Kinetic Properties The Michaelis-Menten constants offree and immobilized quince leaf PPO were calculated byusing Lineweaver-Burk double reciprocal models [14] Thecalculated 119870

119898values for free and immobilized quince leaf

PPO were 586 and 1257mM respectively An increase inthe 119870119898value for catechol on the immobilization of PPO was

observed Our results are similar to the Michaelis-Mentenconstants of partially purified free and immobilized potatoPPO The values of 119870

119898were 80mmol Lminus1 for free potato

PPO and 147mmol Lminus1 for alginate SiO2PPO respectively

In general 119870119898

values of immobilized enzymes are higherthan those for free enzymes revealing an affinity change forthe substrate [17]

0102030405060708090

0 30 60 90 120Time (min)

Dec

olor

izat

ion

()

Neutrilan Black MRXTelon Turquoise M5GLanaset Yellow 4GNTelon Yellow ARB

Isolan Grey NHFSSolophenyl Red 7BEAstrazon Yellow 7GLLTelon Red MGWN

Figure 3 Removal of eight dyes by immobilized quince leaf PPO

34 Effect of pH on the Decolorization of Textile Dyes Theeffects of pH on the decolorization of textile dyes by free andimmobilized quince leaf PPO are summarized in Table 1Theeffect of pHwas studied at pH values between 40 and 70Theresults showed that the decolorization rate was significantlyhigher at lower pH having maximum at pH 40 (Table 1)Also the immobilized PPO increased the decolorizationpercentage compared to the free enzyme There were severalearlier reports regarding themaximumdecolorization of dyesby various plant polyphenol oxidases [17] plant peroxidases[18] microbial polyphenol oxidases [19] and laccases atacidic pH values [13ndash16] When pH is increased above 70the extent of decolorization was decreased rapidly This isan advantage from industrial application point of view sincesome dye effluents are slightly acidic [19] The results alsoshowed that Telon Yellow ARB was the most effectivelydecolorized by immobilized quince leaf PPO at pH 40 with7268 decolorization

35 Effect of Time on the Decolorization of Textile Dyes Theenzymatic decolorization of textile dyes by immobilized qui-nce leaf PPOwas examined by varying the time of incubation(Figure 3)The eight different synthetic textile dyes were usedfor decolorization in this study The results showed that thedecolorization of dyes was increased with time up to 30minHowever the rate of dye decolorization was quite slow after1 h which may be probably due to products inhibition Thisobservation suggested that initial first hour was significantfor dyes decolorizationThese results were in agreement withearlier published work of decolorization of textile dyes [2021] The most effected decolorization by immobilized quinceleaf PPO was observed for the Telon Yellow ARB dye

4 Conclusion

Our results showed that PPO enzyme was successfullypartially purified from quince leaves and immobilized ontoalginate beads Immobilization of quince leaf PPO increasedits stability to pH and temperature that could be more useful


Table 1 Decolorization of textile dyes by quince leaf PPO

Dyes 120582max (nm) Immobilized PPO decolorization () Free PPO decolorization ()pH 40 pH 70 pH 40 pH 70

Neutrilan Black MRX 570 1969 1639 1223 1085Telon Turquoise M5G 616 307 2053 865 33Lanaset Yellow 4GN 398 1962 131 525 275Telon Yellow ARB 364 7268 5152 1525 985Isolan Grey NHFS 576 256 212 622 347Solophenyl Red 7BE 515 3153 2876 2127 1889Astrazon Yellow 7GLL 406 1525 151 663 587Telon Red MGWN 515 421 3675 1735 1128

in industrial applications Free and immobilized quince lea-ves PPO were applied to eight different textile dyes for deco-lorization Immobilized quince leaf PPO enzyme was signifi-cantly more effective in decolorizing of the dyes as comparedto free enzyme at pH 40 Our results clearly demonstratedthat the different textile dyes in wastewater could be easilydecolorized by the partially purified plant PPOobtained fromcheaper plant sources like quince leaves The use of partiallypurified immobilized quince leaf PPO may be extendable tothe effluents coming out of industries and mixtures of dyespresent in wastewaters

Conflict of Interests

The authors declare that there is no conflict of interests regar-ding the publication of this paper

Acknowledgment

This work was supported by Sakarya University Scientific Re-search Foundation (Project no BAP- 2012-02-04-040)

References

[1] P N Patel and H S Patel ldquoRemoval and decolorization of dyebearing textile effluents by sulfinated furfural-acetone resinrdquoAdvances in Applied Science Research vol 3 no 5 pp 2693ndash2699 2012

[2] B K Nandi A Goswami andM K Purkait ldquoAdsorption char-acteristics of brilliant green dye on kaolinrdquo Journal of HazardousMaterials vol 161 no 1 pp 387ndash395 2009

[3] H F Hamid AMoezzi M A Khouzani Y Janlou F Niknejadand M A Faramarzi ldquoSynthetic dye decolorization by threesources of fungal laccaserdquo Research Journal of Chemistry andEnvironment vol 17 no 5 pp 76ndash81 2013

[4] I Eichlerova L Homolka and F Nerud ldquoSynthetic dye decol-orization capacity of white rot fungus Dichomitus squalensrdquoBioresource Technology vol 97 no 16 pp 2153ndash2159 2006

[5] P Pengthamkeerati T Satapanajaru N Chatsatapattayakul PChairattanamanokorn andN Sananwai ldquoAlkaline treatment ofbiomass fly ash for reactive dye removal from aqueous solutionrdquoDesalination vol 261 no 1-2 pp 34ndash40 2010

[6] N Duran and E Esposito ldquoPotential applications of oxidativeenzymes and phenol oxidase-like compounds in wastewater

and soil treatment a reviewrdquo Applied Catalysis B vol 8 no 2pp 83ndash99 2000

[7] Q Husain and U Jan ldquoDetoxification of phenols and aromaticamines from polluted wastewater by using phenol oxidasesrdquoJournal of Scientific and Industrial Research vol 59 no 4 pp286ndash293 2000

[8] A Bhunia S Durani and P P Wangikar ldquoHorseradish peroxi-dase catalyzed degradation of industrially important dyesrdquoBiotechnology and Bioengineering vol 72 no 5 pp 562ndash5672001

[9] A Domınguez S R Couto and M A Sanroman ldquoDye dec-olorization by Trametes hirsuta immobilized into alginate be-adsrdquo World Journal of Microbiology and Biotechnology vol 21no 4 pp 405ndash409 2005

[10] MMatto andQHusain ldquoDecolorization of direct dyes by imm-obilized turnip peroxidase in batch and continuous processesrdquoEcotoxicology and Environmental Safety vol 72 no 3 pp 965ndash971 2009

[11] M Mogharabi N Nassiri-Koopaei M Bozorgi-KoushalshahiN Nafissi-Varcheh G Bagherzadeh and M A FaramarzildquoImmobilization of laccase in alginate-gelatin mixed gel anddecolorization of synthetic dyesrdquo Bioinorganic Chemistry andApplications vol 2012 Article ID 823830 6 pages 2012

[12] PWang X Fan L Cui QWang and A Zhou ldquoDecolorizationof reactive dyes by laccase immobilized in alginategelatin blentwith PEGrdquo Journal of Environmental Sciences vol 20 no 12 pp1519ndash1522 2008

[13] V M Devi L Inbathamiz T M Ponnu S Premalatha and MDivya ldquoDye decolorization using fungal laccaserdquo Bulletin ofEnvironment Pharmacology and Life Sciences vol 1 pp 67ndash712012

[14] H Lineweaver and D Burk ldquoThe determination of enzyme dis-sociation constantsrdquo Journal of the American Chemical Societyvol 56 no 3 pp 658ndash666 1934

[15] L Lu M Zhao and YWang ldquoImmobilization of laccase by alg-inate-chitosan microcapsules and its use in dye decolorizationrdquoWorld Journal of Microbiology and Biotechnology vol 23 no 2pp 159ndash166 2007

[16] A Kunamneni I Ghazi S Camarero A Ballesteros F J PlouandMAlcalde ldquoDecolorization of synthetic dyes by laccase im-mobilized on epoxy-activated carriersrdquo Process Biochemistryvol 43 no 2 pp 169ndash178 2008

[17] J Shao L L Huang and Y M Yang ldquoImmobilization of poly-phenol oxidase on alginate-SiO

2

hybrid gel stability and prel-iminary applications in the removal of aqueous phenolrdquo Journal


of Chemical Technology and Biotechnology vol 84 no 4 pp633ndash635 2009

[18] Q Li Q Yue Y Su B Gao and J Li ldquoTwo-step kinetic study onthe adsorption and desorption of reactive dyes at cationic poly-merbentoniterdquo Journal of Hazardous Materials vol 165 no 1ndash3 pp 1170ndash1178 2009

[19] A Unyayar M A Mazmanci H Atacag E A Erkurt and GCoral ldquoA Drimaren Blue X3LR dye decolorizing enzyme fromFunalia trogii one step isolation and identificationrdquo Enzymeand Microbial Technology vol 36 no 1 pp 10ndash16 2005

[20] A A Khan and Q Husain ldquoDecolorization and removal of tex-tile and non-textile dyes from polluted wastewater and dyeingeffluent by using potato (Solanum tuberosum) soluble andimmobilized polyphenol oxidaserdquo Bioresource Technology vol98 no 5 pp 1012ndash1019 2007

[21] AA Khan andQHusain ldquoPotential of plant polyphenol oxida-ses in the decolorization and removal of textile and non-textiledyesrdquo Journal of Environmental Sciences vol 19 no 4 pp 396ndash402 2007

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Anatomy Research International

PeptidesInternational Journal of


Hindawi Publishing Corporation httpwwwhindawicom

International Journal of

Volume 2014

Zoology


Molecular Biology International

GenomicsInternational Journal of


The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014


BioinformaticsAdvances in

Marine BiologyJournal of



Signal TransductionJournal of


BioMed Research International

Evolutionary BiologyInternational Journal of



Biochemistry Research International

ArchaeaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014


Genetics Research International


Advances in

Virolog y

Hindawi Publishing Corporationhttpwwwhindawicom

Nucleic AcidsJournal of

Volume 2014

Stem CellsInternational



Enzyme Research



Microbiology


celite controlled porosity glass chitosan microspheres andalginate [9ndash13]

In this study our first objective was to find a cheaper andeasily available alternative plant polyphenol oxidase (PPO)enzyme source for the commercially available ones and itsimmobilization Quince leaves (Cydonia Oblonga) which arewaste in Turkey have been employed in this work as an easilyavailable and inexpensive PPO enzyme source PPO enzymewas partially purified from quince (Cydonia Oblonga) leavesand immobilized on calcium alginate beadsThe biochemicalproperties were determined for free and immobilized quince(Cydonia Oblonga) leaf PPO The second objective was toevaluate the performance of free and immobilized polyphe-nol oxidases regarding the decolorization of various reactiveacid direct and basic dyestuffs

2 Materials and Methods

21 Materials Quince (Cydonia Oblonga) leaves used in thisstudy were obtained from Sakarya region Turkey and sto-red at ndash20∘C until used Polyvinylpolypyrrolidone (PVP)(NH4)2SO4 Sodium alginate CaCl

2 and other chemicals

were obtained from Sigma Chemical Co and dyes wereprovided by kindly DyStar Huntsman and Yorkshire

22 Extraction and Purification 30 g of quince (Cydonia Obl-onga) leaves was obtained from local Sakarya regionThe leafsamples were added to 50mM sodium phosphate buffer (pH70) 05 g polyvinylpolypyrrolidone (PVPP) and 10mMascorbic acid and themixturewas homogenizedwith blenderAfter the filtrate was centrifuged at 14000 g for 30min thesupernatant was collected Extraction was fractionated with(NH4)2SO4 solid (NH

4)2SO4was added to the supernatant

to obtain 80 saturation The mixture was centrifuged at14000 g for 30 minutes and the precipitate was dissolved ina small amount of phosphate buffer and then dialyzed at 4∘Cin the same buffer for 24 h with three changes of the bufferduring dialysis The dialyzed enzyme extract was collectedand used for all other processes

23 Enzyme Immobilization Alginate solution (1 2 3 wv)was prepared by dissolving sodium alginate in deionized wa-ter Crude quince leaf PPO solution was mixed with 20mL ofalginate solution at the enzymealginate ratio of 1 10 (vv)Themixture was stirred with magnetic stirring to ensure thatcomplete Ca-alginate beadswere produced as soon as the em-ulsion was added into 100mL 3M CaCl

2(1 2 3 wv) The

beads were allowed to harden for at least an hour under mildagitationThen the Ca-alginate beads were removed from theencapsulation medium via centrifugation and rinsed twicewith 05 (wv) CaCl

2containing 1 (vv)

24 PPO Activity Assay The activity of free and immobilizedPPO was determined at room temperature using catechol asa substrateThe assay mixture consisted of 295mL of 20mMcatechol in 005M potassium phosphate buffer pH 70 and005mL of enzymeThe increase in absorbance at 420 nmwasmeasured as a function at time for 1min One unit of enzymeactivity is defined as the amount of the enzyme that causes an

increase in absorbance of 0001 per min at 25∘C PPO activitywas assayed in triplicate measurements

For determining Michaelis constant (119870119898) and maximum

velocity (119881max) values of the enzyme PPO activities weremeasured with catechol at varying concentrations underoptimum conditions of pH and temperature 119870

119898and 119881max

values of PPO for catechol substrate were calculated froma plot of 1119881 against 1[119878] by the method of Lineweaver andBurk [14]

25 Influence of pH The activity assays were carried out overthe pH range 35ndash90 Reaction rates of free and immobilizedenzyme preparations depending on pH were investigatedusing 50mM acetate buffer at pH 35 40 50 and 50mMand phosphate buffer at pH 60 70 75 80 and 90 Activityof pH profiles was determined at various pH values in 10mMcatechol solution at 25∘C

26 Influence of Temperature The effect of temperature onenzyme activity was investigated in the range of 4ndash70∘C forboth free and immobilized PPO enzymes Activity of tem-perature profiles was determined at indicated temperaturesin 10mM catechol solution (pH 70)

27 Effect of pH and Time on the Decolorization of TextileDyes Neutrilan Black MRX (CI Acid Black 194) TelonTurquoise M-5G (CI Direct Blue 86) Lanaset Yellow 4GN(CI ReactiveYellow 39) TelonYellowARB (CI AcidOrange67) Isolan Grey NHFS (CI Acid Black 220) Telon RedMGWN Solophenyl Red 7BE and Astrazon Yellow 7GLL(CI Basic Yellow 21) dyes were selected for this study Eachdye was incubated with soluble and immobilized quince leafPPO 15 EUmL in the buffers of varying pH values 40ndash70 at25∘C Each dye was also incubated with immobilized quinceleaf PPO 15 EUmL in pH 40 at 25∘C for 30ndash60ndash90minDye decolorization by PPO was monitored at the specificwavelength The decolorization percentage was calculated bytaking untreated dye solution as control of each buffer (100)

28 Calculation of Dye Decolorization Rate Startingabsorbance at characteristic max for each dye (control) wasdesignated as 100 The extent of decolorization rate wasdefined by the following formula

Decolorization percentage () =(119860119900minus 119860)

119860119900

times 100 (1)

where 119860119900is the absorbance of the untreated dye and 119860 is the

absorbance after treatment [15]

3 Result and Discussion

31 Effect of pH on Free and Immobilized PPO For thedetermination of the effect of pH on free and immobilizedenzymes by acid phosphate buffers were used within the pHrange of 35ndash90 The optimum pH for free and immobilizedquince leaf PPO was 75 respectively (Figure 1) Both freeand immobilized quince leaf PPO gave similar pH valuesHowever the immobilized leaf PPO gave much broader pH


0

20

40

60

80

100

3 4 5 6 7 8 9pH

Rela

tive a

ctiv

ity (

)


0

20

40

60

80

100

0 10 20 30 40 50 60 70

Rela

tive a

ctiv

ity (

)

Temperature (∘C)










In general 119870119898


0102030405060708090

0 30 60 90 120Time (min)

Dec

olor

izat

ion

()






4 Conclusion









Acknowledgment


References



















2















Volume 2014

Zoology






















Advances in

Virolog y



Volume 2014




Enzyme Research



Microbiology


0

20

40

60

80

100

3 4 5 6 7 8 9pH

Rela

tive a

ctiv

ity (

)


0

20

40

60

80

100

0 10 20 30 40 50 60 70

Rela

tive a

ctiv

ity (

)

Temperature (∘C)










In general 119870119898


0102030405060708090

0 30 60 90 120Time (min)

Dec

olor

izat

ion

()






4 Conclusion









Acknowledgment


References



















2















Volume 2014

Zoology






















Advances in

Virolog y



Volume 2014




Enzyme Research



Microbiology








Acknowledgment


References



















2















Volume 2014

Zoology






















Advances in

Virolog y



Volume 2014




Enzyme Research



Microbiology














Volume 2014

Zoology






















Advances in

Virolog y



Volume 2014




Enzyme Research



Microbiology

research article the enzymatic decolorization of textile...

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