微生物生态学课件

Microbiologyandplantinteractionsresistenceonheavy-metalPage2Heavymetalsbeingtransferredtohumansviathefoodchainwouldfinallythreatenhumanbeingshealth.Heavy–metalpollutantsPage3Page4BioremediationonheavymetalsPage5MetalresistanceofmicroorganismsPlantrhizospherebacteriaPlantendophyticbacteria•Growinplantrootsystem.•Withbacteria,actinomycetes,fungi,algae,andtheprotozoa.•Alternaterelationshipbetweenthemandplant.•Plantrootsinteractionandpromoteeachother.RhizospherebacteriaBacteria•Widelydistributed,manyvarieties,fastmetabolismandreproduction.•Chemicalcompositionofbacterialcellwallscontainmanyheavymetalionsadsorptiongroups,suchascarboxyl,amino,hydroxyl.CyanobacteriaFungi•Smallmold,single-celledyeastandfruitingbodyoflarge-scalefungus.•Theircellwallscontainconsistslargelyofchitinandglucan.•Fungihavepotentialforheavymetaladsorptionability.SaccharomycesCerevisiaeWhite-rotfungiadsorbePb2+,thehighestremovalratecanreach95%.BlackrhizopusadsorbeAg+,Pb2,Li+andCd2+,Zn2+andNi2+,Cu2+,suchasheavymetalions.Alage•Widedistribution,agoodbiologicaladsorbent.•Thewallsofalgaehasalargersurfacearea.•Cellwallshaveacertainchargeandviscous,thesecharacteristicsmakethemetalionhastheability.ScenedesmusObliquus•HasalargeradsorptioncapacitytoUO22+.•TheUO22+concentrationinthewaterfrom5.0mg/Lfellto0.05mg/L.•Akindofparasiticbacteriainplantbody,allplantshaveendophytes.•Endophyticbacteria(PGPB)isakindofparasiticlife,promotethegrowthofthehost.•Canenhanceplantresistancetopathogens,drought,heavymetal.Endophyticbacteria•FromElsholtziasplendensandduckplantargrass(Commelinacommunis).•Firmicutes,Actinobacteria,Proteobacteria.•Thesebacteriastrainsincopperresistanceofmaingroups.TheCr6+resistantplantgrowthpromotingbacteria(PGPB),Pseudomonassp.PsA4andBacillussp.Ba32wereisolatedfromheavymetalcontaminatedsoilsandtheirplantgrowthpromotingactivityontheIndianmustard.•Releaseofchelatingagentandironcarrier.•Acidificationofthesoilenvironment,•ChangetheREDOXpotential.•Reducetheabsorption.•Increasethedischarge•OxidationreductionModeofresistancetoheavy-metalMechanismsofresistencetoheavy-metalInteractionOxidationReduceAdsorptionAcidificationbondedIncreaseReducetheabsorptiontheheavymetalcontentinthemicrobialcellsatalowlevelismaintainedwithoutcausingtoxiceffectsoncells.AsatypeofstaphresistanceofCd2+isthecase.Increasethedischarge•somemicroorganismsmaybeproactivemannerbyheavymetalionswithinthecellisdischargedoutsidethecell,thusmaintaininglowlevelsofthecell.•AsonekindofresistancetoBacilluscopper.Oxidationreduction•manymicrobialoxidationorbyreduction(inmostcases)fromthehightoxicityoftheheavymetaltransformedintolesstoxicvalencevalencestate,therebyliftingtheheavymetaltoxicity.•Forexample,theresistanceofmercurythatisthecase.Bondedtotheoutercells•Reducingtheconcentrationoftoxicheavymetalsintheenvironment,thepurposeofdetoxification.•Escherichiacolicopperresistanceeffectasthatisso,itcanbesecretedproteinscapableofbindingtocopperions,therebyreducingtheeffectiveconcentrationofcopperions.AdsorptionManymicrobialcellsurfacehasaspecialstructure,canabsorbheavymetalionsandthustoreducetheconcentrationofheavymetalionsinsolution.Currentresearchprogress•Mustard(Brassicajuncea)andCr-resistantstrains.Cr-resistantstrainsplantappliedtoMustardIncreasebiomessresault•Cr-resistantstrainsPseudomonassp.PsA4andBacillussp.Ba32appliedtomustard(Brassicajuncea).•TheresultsshowedthatvaccinatedPsA4mustardorBa32haveincreasedin95.3mg/gand198.3mg/gCr(6+)biomassinthesoil.•Castor(Ricinuscommunis)andnickel,zincresistancestrains.isolateelecteinoculateincrease•isolatedfromtherhizospheresoilmicrobes,afternickel,zincresistancescreening.•electedtheheavymetalresistantstrainsPseudomonassp.AndPseudomonasjessenii.•inoculatedthemtocastor(Ricinuscommunis),theyfoundasignificantincreasecastorbiomass,andincreasedtheaccumulationofZn,Ni,Cu's.Prospects•Heavymetalcontaminationofsoilgrowingprobleminmanyoptionsinphytoremediationhasitsuniqueadvantages,thefocusoftheproblemishowtoincreasetheresistanceofplantstoheavymetals.•Asanewway,biologicalcontrolhashugepotential,butisstillinitsinfancy.Withfurtherresearch,itisexpectedtofindmoremicrobialresources,anddevelopingnewtechnologiestomakepracticalapplicationspossible.