水环境中微生物及其胞外聚合物与重金属作用机理研究

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1、贵州师范大学硕士学位论文水环境中微生物及其胞外聚合物与重金属作用机理研究姓名：康福星申请学位级别：硕士专业：环境科学指导教师：龙健20090401贵州师范大学硕士学位论文ABSTRACTExwacellularpolymericsubstance(EPS)secretedbymicroorganismplaysanimportantroleinpharrnaey,culturedmilkandwastewatertreatmentinenvironment．Inordertounderstandthecombiningmechanismb

2、etweenmicroorganism&itsextracellularpolymericsubstanceandheavymetals，thestudyusesastimulatingmethodinlaboratorytograduallyunderstandatlargerelationshipofthreeaspectsasfollows：physiologicalresponseofmicroorganismtoheavymetalstress，changingEPSpropertyinducedbyheavymetalandt

3、hecombiningmechanismbetweenEPSandheavymetals．Theresultsshowinthefollowing．Firstly,existingCa+CalldecreasestressofheavymetalCdonalgalcells，andprotectcellsfrommoredamage，whichcanbeattributedtoprotectingeffectofcalcificationlayerstriggeredbybio—calcification．Secondly,slightC

4、uCaninduceSynechocystissp．toproducemoreprotein-likeandsolublemicrobialproduct—likeEPSthatisMW>14．000Da．AndhumusinEPSisnotfromsecretionofmicroorganism，butdecayinganddecomposingmicroorganismisitssource．Finally,theresultsaboutcombiningmechanismbetweenheavymetalCdandtwoEPSssh

5、owthatanobviousquenchingeffectofLBtriggeredbyCdconcentrationlessthanlxl04mol·L．1CanbeobservedatpHvalue4．ThephenomenathatWasquenchedatlowerpHvaluewasnotonlyrelated埘也theprotonationeffectoffluorophores．butalsolinked、撕mthechangeofcombiningsitesbetweenCdandprotein-like．Inaddit

6、ion,fortheanalysisoffurtherthree—dimensionalfluorescencespectrum，fluorophoresofprotein-likeinLBhavecharacterofsingleness，whereasfluorophoresofTBhaveacharacteristicofdiversity．AtpH10quenchingoffluorescencepeaksofprotein-likeinLBandTBaleresultedfromtwoaspects，ontheonehand，i

7、tWasrelated州tlltheproductionofEPS·Cdcomplex，and011theotherhanditcanbeattributedtocollidingquenchingbetweenfluorescencemolecules．Inthestudy,theoreticalinnovationonfluorescencetitrationisnotonlyexhibitedbutalsotheseconclusionswillhelpUStounderstandtheself-purificationofwate

8、rcolumnsinheavymetals．II贵州师范大学硕士学位论文Keywords：Microorganism，Extracellularpolymericsubstance(EPS)，