Technical use of microbial enzymes in Textile, leather and diagnostic purposes

1. ShaheenAlam
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Technical use of Microbial Enzymes
I will discuuss here only on folloeing topis
1. Application of Microbial enzymes in Textile Industry
2. Application of Microbial enzymes in Leather Industry
3. Application of Microbial enzymes in Diagnostic purposes
Topic no. 1:- Application of Microbial enzymes in Textile Industry
The use of microbial enzymesintextile industryisone of the mostrapidlygrowingfieldinindustrial
Enzymology because Historically,the use of enzymesinthe textile industrybeganin1912 withthe use
of barleyforstarch sizingfromwovenfabrics.The firstmicrobial enzyme, ‘amylase’,wasusedin1950
for the same starch desizingprocessthatisnowadaysaroutine procedure.Today,microbialenzymes
are importanttoolsinthe textile industry,astheirnon-toxicandeco-friendlycharacteristics withthe
increasinlyimportantrequirementsfortextilemanufacturestoreduce pollutionintextile production
Presently,the textile industryisemployingan arrayof approximately75 enzymesthatcouldbe broadly
groupedas oxidoreductasesandhydrolases.The differentprocessesinwhichenzymesfindapplication
are :-
1) textile desizing,
2) enzymaticscouring,
3) denimfinishing,
4) biopolishing,
5) degummingof silk,
6) and fiberprocessing.

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Table: Microorganismsproducing enzymesoftextile important
Enzyme applications intextile preparatory process
1) Enzymatic Desizing
Cottonor blendedfabricsuse warpthreadscoatedwithadhesive knownas‘size’.Size helpsin
lubricating,thusprotectingthe yarnfromabrasionandpreventingthe threadsfrombreakingduring
weaving.Starchandits derivativesare mostcommonlyusedforthisprocessastheyhave excellent
filmformingcapacity,are easilyavailable,andare relativelycheaper.Afterweaving,the sizingagentand
othernon-cellulosicmaterial presentonthe cottonfibermust be removedforthe processof dyeingand
finishing. In the textile industryamylasesare usedtoremove starch-basedsize forimprovedand
uniformwetprocessing.Amylaseisahydrolyticenzymewhichcatalysesthe breakdownof dietary
starch to short chainsugars,dextrinandmaltose.The advantage of these enzymesisthattheyare
specificforstarch,removingitwithoutdamagingtothe supportfabric.Anamylase enzyme canbe used
for desizingprocessesatlow-temperature (30-60ºC) andoptimumpHis 5.5-6.5 .
2) Enzymatic Scouring (Bioscouring)
Untreatedcottonor greige containsvarietiesof cellulosicimpuritieslikewaxes,pectins,and
hemicelluloses,whichgive hydrophobicpropertiestothe fiberandtherebyinterfereinthe processof
dyeingandfinishing.Thus,scouringiscarriedouttoremove these impuritiesandenhance wettabilityof

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the fiber.Thiswas previouslyconductedwithchemical methods;however,nowadaysbioscouringis
carriedout usingmicrobial enzymes likepectinases,proteases,lipases,andcutinases – individuallyor
incombination. Pectinasesisageneral termappliedforpectinesterases,polygalacturonases,andpectin
lyases.
In thispectinasedestroythe cotton cuticle structure (Cuticleis a thin layerof cutin and Cutin is polyester
composed of epoxy and hydroxylfatty acids.) bydigestingthe pectinandremovingthe connection
between the cuticle andthe bodyof cottonfibre whereas cellulasecandestroycuticle structure by
digestingthe primarywall celluloseimmediatelyunderthe cuticle of cotton.Cutinases (cutinasefroma
bacterial source, P. mendocina ) are hydrolyticenzymesthatdegrade the cutin .Handle isverysoftin
enzymaticscouringcomparedtoharshfeel inalkaline scouringprocess.Enzymaticscouringmakesit
possible toeffectivelyscourfabricwithoutnegativelyaffectingthe fabricorthe environment.It also
minimiseshealthrisksenceoperatorsare notexposedtoaggressivechemicals .
3) Enzymatic Bleaching
The purpose of cotton bleachingistodecolourise natural pigmentsandtoconfera pure white
appearance tothe fibres.Mainlyflavonoidsare responsible forthe colourof cotton. The most common
industrial bleachingagentishydrogenperoxide.Conventional preparationof cottonrequireshigh
amountsof alkaline chemicalsandconsequently,huge quantitiesof rinse waterare generated.However,
radical reactionsof bleaching agentswiththe fibre canlead toa decrease inthe degree of
polymerisationand,thus,tosevere damage.
Therefore,replacementof hydrogenperoxide byanenzymaticbleachingsystemwould notonlyleadto
betterproductqualitydue tolessfibre damage butalsoto substantial savingsonwashingwaterneeded
for the removal of hydrogenperoxide.Analternative tothisprocessistouse a combinationof suitable
enzyme systems.Amyloglucosidases,pectinases,andglucoseoxidases are selectedthatare compatible
concerningtheiractive pHand temperature range.
Some researchabstractson bioleachingare givenbeow-
i. Tzanovet al.(2003) reportedforthe firsttime the enhancementof the bleachingeffect
achievedoncottonfabricsusinglaccasesinlow concentrations.Inaddition,the shorttime of
the enzymaticpre-treatmentsufficienttoenhance fabricwhitenessmakesthisbio-process
suitable forcontinuousoperations.
ii. Also,Pereiraetal.(2005) showedthata laccase froma newlyisolatedfungal strainof Trametes
hirsuta, wasresponsibleforwhitenessimprovementof cottonmostlikelydue tooxidationof
flavonoids.
iii. More recently,Bastoetal.(2006) proposeda combined ultrasound-laccase treatmentforcotton
bleaching.Theyfoundthatthe supplyof low ultrasoundenergy(7W) enhancedthe bleaching
efficiencyof laccase oncottonfabrics.Natural fabricssuch as cottonare normallybleachedwith
hydrogenperoxide before dyeing.Catalaseenzyme isusedtobreakdownhydrogenperoxide
bleachingliquorintowatermoleculesandlessreactivegaseousoxygen.Comparedwiththe

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traditional clean-upmethods,the enzymaticprocessresultsincleanerwaste waterorreduced
waterconsumption,areductionof energyandtime.
4) Biopolishing
Biopolishingisafinishingprocessthatimprovesfabricqualitybymainlyreducingfuzzinessandpilling
propertyof cellulosicfibre.The objectiveof the processiseliminationof microfibrils of cottonthrough
the action of cellulaseenzyme .The maincharacteristicsimpartedtothe fabricduringbiopolishing
treamentare as follow:
i. Cleanersurface isobtainedconferringacoolerfeel.
ii. Lustre is obtainedasa side effect
iii. Fabricobtainssofterfeel.
iv. Tendencyof the fabricto pill ends.
5) Enzymatic treatment to denim
Denimsare basicallycottoncloththat isconventionallydyedwithindigo,havingacharacteristicblue
color.The stonewashorwornlookispopularindenimfinishingandwasinitiallyachievedbylaundering
the denimwithabrasive pumice stones (sodiumhypochloriteorpotassiumpermanganate).
Disadvantage of these methodare asfollows:
i. Pumice stonescause large amountof back-staining.
ii. Pumice stonesare requiredinverylarge amount.
iii. Theycause considerable wearandtearof machine.
These disadvantagesleadtogive rise the processof use of enzymes.Cellulase enzymeisusedindenim
washing. Cellulasepossessasimilaractionbylooseningthe indigodye fromthe denimfibers,givinga
fadedabradedlook similartothatprovidedbythe stones ina processknow as “BioStonewashing”.A
small dose of enzyme canreplace several kilogramsof pumice stones.The use of lesspumice stones
resultsinlessdamage togarment,machine andlesspumice dustinthe laundryenvironment. More
recently,some authors showedthatlaccase wasaneffective agentforstonewashingeffectsof denim
fabricwithand withoutusingamediator .

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Table: Enzymesusedin textile and theireffects
Table: Applicationof hydrolase enzyme infabric production

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Table: applicationof oxidoreductase infabric preparation
Topic no. 2:- Application of Microbial enzymes in Leather Industry
Leather Industry :-
Microbial Enzymeshave beenusedintanneriesandthe leatherindustryforcenturiesastheywere
efficientindegradingthe proteinandlipidcomponentsof the hides/skin.Inearlydays,these enzymes
were derivedfromanimal excretaandlaterthe pancreas of cattle.
Leather-processingindustriesinvolvemanysequential stepsfromraw hidestoprocessedleather.The
stagesof leatherprocessingare :-
i. preservation,
ii. soaking,
iii. liming,
iv. dehairing,
v. flashing,
vi. splitting,
vii. reliming, deliming,
viii. bating,
ix. degreasing,
x. frizzing,
xi. beaching,
xii. pickling,depickling,
xiii. and tanning.

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Raw hidesundergomanyof these treatmentsinacascade mannerbefore itisconvertedintofinished
leather.
Disadvantageofconventional Leather processing
The pre-tanningoperations requirethe use of harshchemicalsinlarge amounts,hence the leather
industryisone of the worst environmental pollutionoffenders.
Advantageof microbial enzymein Leather processing
1) Duringleathermanufacturing,the non- collagenousconstituentsof raw hidesare completely
removedduringpre-tanningoperations,of whichdehairingisone of the majorprocesses.
Dehairingisthe single largestprocessinthe leatherproductionprocessandrequiresahuge
numberof enzymeslike proteases,amylases,and lipasestomake the processenvironmentally
friendly.
2) Today,microbesserve asresourcesof highlyspecificenzymesthatare fastintheiractionand
are therefore usedintanneriesforsoakinganddehairingprocesses.
3) Otheradvantagesof usingthese enzymesincludethe replacementof harmful chemicalsthat
pose a threatto the environmentandreductionsinprocessingtimesandproductioncosts
Role of enzymes indifferent Leather processing stages :-
1) Curing : Curingof the hide isdone to preserve themsotheydonotspoil before theyare
subjecttofurtherprocessingforleatherdevelopment.Hidesare steepedinabrine bathand
driedinthe sun; saltisaddedto the fleshside.
2) Soaking :- Soaking isthe first tanningoperationthatinvolvesthe treatmentof hideswith
water.Soakingisusedto rehydrate the skin.The degree of rehydrationaffectsthe qualityof
leather;the betterthe rehydration,the superiorthe leather.Soakingsolutionsgenerally
comprise surfactantsandantimicrobial compounds.Ithasbeenfoundthatbrine andcured
hides,whensoaked inproteaseinthe presence of surfactants,reducedthe soakingtime by45
%,and sulphidesreducedby40 %.
3) Liming :-Limingisemployedonimproperlysoakedskin.These are re-soakedinmilkof lime
so that the desiredswellingof collagentakesplace andopensupthe fiberbundles.The

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objective of thisprocessistoremove hairs,nails,hooves,andotherkeratinousmaterials.
Alkalineproteases andalkalinelipases are usedin the processof soakingand liming.The
protease will openthe membranesaroundthe fatcells,makingthe fataccessible tolipase,
resultinginthe breakdownof fats.Furthermore,the breakdownproductsshall emulsifyintact,
whichshall distributethroughoutthe feltomittingthe use of degreasingsurfactants.NovoLime
® is a protease/lipaseblendforenzyme-assistedlimingof hidesandskins.
4) Dehairing : Dehairinginvolvesthe removingof hairsfromthe hideswithoutdamagingthe
hide,whichdependsonthe phenomenonof hairloosening.Specific proteasesare requiredthat
can remove the hairwithoutdamagingthe fibrouscollagen.Clarizyme® is an alkalineserine
protease from Aspergillus flavus by the Central LeatherResearchInstitute (CLRI),Chennai,
India,forthe dehairingof skinandhides.ProteasesfromBacillusand Streptomyces have been
usedforenzymaticdehairingprocesses.
5) Bating :- Bating isa processof beatingthe leather cruellywithaheavystroke usingwooden
logsand metal rods.Thisprocessiscarried outto loosenandpeptize non-collagenousskin
structuresviaremoval of interfibrillaryproteins,epidermis,andscuds.Forthe productionof soft
pliable leather,usedformakingpursesandgloves,astrongbeatingprocessmustoccur.
Thisprocessis generallycarriedoutinthe presence of proteolyticenzymesofbacterial origin.Effective
batingoccurs underalkaline conditionsconductedat95–100 °F (30–38 °C) between apHof 7.5 and8.5
or else the enzyme efficiency.
6) Degreasing :- Grease removal intanneryiscarriedout vialiming.However,the grease
contentinsome hides/skinsishigherandcausesfattyacid spuesandunevendyeingand
finishing.A variety ofmicrobial lipases have beenusedfordegreasing.The beststage of
degreasingispickling,asall the fatdepositsare available tothe surfactants.Since picklingisan
aqueousphase,acombinedactionof disruptionof fatcellsandtriglyceride splittingoccurs,
therebyimprovingthe degreasingprocess.
7) Tanning :-Tanningis the laststage of leathermanufacture whereincollageniscross- linked
to the active groupof the tanningagent,therebyirreversiblystabilizingthe skinthatisprone to
putrefaction.Thismakesthe collagenresistanttobacterial,enzymatic,andacidattack.

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Topic no. 3:-Application of Microbial enzymes in Diagnostic purposes
Diagnosticenzymesare definedasa componentof an assaysystemfordeterminationof manydifferent
substances.These are generallyemployedfordiagnosis/biomarkersof diseasesanduse blood,serum,
and urine foranalysis.Microbial enzymesare alsoused asindicatorsorbiomarkersof a disease.
1) Sialidasesare bacterial enzymesthatplaya role incellularinteractions,bacterial nutrition,and
immune response evasion,thusimprovingthe bacterial abilitytoadhere to,invade,anddestroy
the mucosal tissue.Sialidasesoccurinbacteria,mycoplasma,protozoa,fungi,andviruses.
Bacterial vaginosis(BV) isadisorderof the vaginal ecosystemcharacterizedbyashiftinthe vaginal flora
formthe normallypredominant Lactobacillus tomixedflora,including Gardnerellavaginalis,
Mobiluncus, Prevotella,Bacteroides,and Mycoplasma species.BVBluesystem(GryphusDiagnostics,
L.L.C.) isa chromogenicdiagnostictestbasedonthe presence of elevatedsialidase enzymesinvaginal
fluid samples.
2) Microbial mucinases(mucin-degradingenzymes)are associatedwithgenital tractconditions
and sexuallytrans-mitteddiseases(STDs).

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Table: Exampleof microbial enzymesused for analytical,diagnosticandtherapeutic purposes