Biosorption of chromium and nickel by heavy metal resistant fungal and bacterial isolates

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JournalofHazardousMaterials146(2007)

270–277

Biosorptionofchromiumandnickelbyheavymetal

resistantfungalandbacterialisolates

ShankarCongeevarama,∗,SrideviDhanarania,JoonhongParkb,

MichaelDexilina,KaliannanThamaraiselvia,∗

aDepartmentofEco-Biotechnology,BharathidhasanUniversity,Tiruchirappalli620024,TamilNadu,IndiabSchoolofCivilandEnvironmentalEngineering,YonseiUniversity,Seoul120-749,SouthKorea

Received4May2006;receivedinrevisedform8December2006;accepted9December2006Availableonline13December2006

Abstract

Microorganismsplayasignificantroleinbioremediationofheavymetalcontaminatedsoilandwastewater.Inthisstudy,heavymetalresistantfungiandbacteriawereisolatedfromthesoilsamplesofanelectroplatingindustry,andthebioaccumulationsofCr(VI)andNi(II)bytheseisolateswerecharacterizedtoevaluatetheirapplicabilityforheavymetalremovalfromindustrialwastewaters.TheoptimumpHandtemperatureconditionsforboththegrowthandheavymetalremovalweredeterminedforeachisolate.TheoptimalpHforfungalisolateswaslower(5–5.2)thanthatforbacterialisolates(7).Theobservedeffect(s)ofpHwasattributablemainlytoorganism-specificphysiologybecauseinallthetestedcasesthecellulargrowthpositivelycorrelatedwithheavymetalremoval.Batchandtoleranceexperimentsprovidedinformationforsolidretentiontime(SRT)designandthelethaltolerancelimitsfortheisolatedmicroorganisms.ExperimentalresultsindicatedthatexpandedSRTs(stationaryphase)canberecommendedwhileusingthefungalandbacterialCr-resistantisolatesforremovingchromium.InthecaseofNi-resistantbacterialisolate,anon-expandedSRTwasrecommendedfordesigningcontinuous-flowcompletelystirred(CFCS)bioreactorsothatamid-logphaseofcellulargrowthcanbekeptduringthebioaccumulationprocess.ThetolerancedatawithahighrangeofheavymetalconcentrationsrevealedtheCr-resistantisolates,especiallythefungalone,couldtoleratechromiumtoxicityatupto10,000mgL−1chromium.ResultindicatestheapplicabilityoftheisolatedMicrococcussp.andAspergillussp.fortheremovalofchromiumandnickelfromindustrialwastewater.©2006ElsevierB.V.Allrightsreserved.

Keywords:Fungi;Bacteria;Bioaccumulation;Metalbioremediation;pH;Temperature;Tolerance

1.Introduction

Chromiumandnickelarereleasedintotheenvironmentby

alargenumberofprocessessuchaselectroplating,leathertan-

ning,woodpreservation,pulpprocessing,steelmanufacturing,

etc.,andtheconcentrationlevelsofchromiumandnickelinthe

environmentwidelyvaries.Thesetwometalsareofmajorcon-

cernbecauseoftheirlargerusagesindevelopingcountriesand

theirnondegradabilitynature.Hexavalentchromiumishighly

solubleinwaterandcarcinogenictohuman.Ni(II)ismoretoxic

andcarcinogenicmetalwhencomparedwithNi(IV).Dueto

theirtoxiceffectsonlivingsystemsstringentlimitshavebeen

stipulatedforthedischargeofchromiumandnickelintothe

∗Correspondingauthors.E-mailaddress:chengaishankar@yahoo.co.in(S.Congeevaram).environment.AccordingtoISI:BureauofIndianStandard(BIS)

theindustrialeffluentpermissibledischargelevelofCr(VI)and

Ni(II)intoinlandwateris0.1and3.0mgL−1,respectively.

Conventionalphysicochemicalmethodssuchaselec-

trochemicaltreatment,ionexchange,precipitation,reverse

osmosis,evaporation,andsorption[1,2]forheavymetalremoval

fromwastestreamsarenotcosteffective[3]andhencebiologi-

calapproachhasbeenconsideredasanalternativeremediation

forheavymetalcontamination.Recentlymicrobialsystems

likefungus,bacteriaandalgaehavebeensuccessfullyusedas

adsorbingagentsforremovalofheavymetals[4–7].Micro-

bialpopulationsinmetalpollutedenvironmentsadapttotoxic

concentrationsofheavymetalsandbecomemetalresistant[8].

DifferentspeciesofAspergillus,Pseudomonas,Sporophyticus,

Bacillus,Phanerochaete,etc.,havebeenreportedasefficient

chromiumandnickelreducers[9,10].Theresponseofmicroor-

ganismstowardstoxicheavymetalsisofimportanceinviewof

0304-3894/$–seefrontmatter©2006ElsevierB.V.Allrightsreserved.doi:10.1016/j.jhazmat.2006.12.017S.Congeevarametal./JournalofHazardousMaterials146(2007)270–277271

theirinterestinthereclamationofpollutedsites.Inthepresent

investigation,theabilityofisolatedfungalandbacterialstrains

towardsremediationofchromiumandnickelwasevaluated

bycharacterizingthebioaccumulationofthesemetals.Effect

oftemperature,pH,andtolerancetotheheavymetalsbythe

isolatedorganismswerecarriedout.

2.Materialsandmethods

2.1.Sampling

Soilsampleswerecollectedfroma30-year-oldsmallscale

electroplatingindustryatSipcot,Velloredistrict,TamilNadu,

Indiathatuseschromiumandnickelformetalplating.Inthe

soilsamplecollected,thechromiumandnickelconcentration

wereapproximatelybetween100and50mgL−1,respectively.

Otherreportedliteraturevaluesforcontaminationinsoilare

chromium:4700mgkg−1andnickel:5100mgkg−1[11].The

collectedsampleswerestoredat−80◦Cbeforeanalysis.

2.2.Isolationofmetal-resistantmicroorganisms