Chapter-5-Extraction(1)

12020/3/23Chapter5Extraction5.1Introduction5.1.1Definition5.1.2Advantages5.1.3Classificationofextraction5.1.4Two-phaseaqueousextraction5.2Extractionprinciples5.2.1ChemicalThermodynamicsofPartitioning5.2.2Selectivity5.2.3Factorsaffectingpartitioncoefficient5.2.4Modelsdevelopedtodescribethepartitioningofbiomolecules5.2.5Howtoachieveeffectivepartitioningorextraction5.2.6CountercurrentStageCalculations5.3ScaleupandDesignofExtractors22020/3/23Chapter5Extraction5.4Reversemicelles5.5Supercriticalfluidsextraction(SFE)32020/3/235.1.1DefinitionExtractionisaprocessinwhichtwophasescomeintocontactwiththeobjectiveoftransferringasoluteorparticlefromonephasetotheother(通过两相接触使溶质从一相转移至另一相）.5.1IntroductionIttakesadvantageofthepartitioningofasolutebetweenimmiscible(互不混溶的)(forexample,waterandorganicsolvents)orpartiallyimmisciblephasesaccordingtoitssolubilityindifferentphases,andthesolutecanbemoreeasilyandspecificallyrecovered.42020/3/23PhaseseparationandpartitioningequilibriaMixturesolutionExtractionsolventraffinatephasexextractionphasey5.1Introduction)*(cckdtdc52020/3/23PenicillindissolvesmorereadilyinamylacetatethaninwateratpH5.5.Citricacidismoresolubleinmethylamylketone(甲基戊基甲酮)thaninwateratpH4.-amylaseismoresolubleinPEG(polyethyleneglycol，聚乙二醇)solutionthanin(NH4)2SO4solution.5.1Introduction62020/3/235.1.2Advantages•Significantlyreducethevolumeofsuspensionassoonaspossibleintheprocess•Canseparatethedesiredproductfromcellsorcelldebrisdirectly5.1.3Classificationofextraction•Liquid-liquidextraction•solid-liquidextraction•supercriticalfluidextraction(orgasextraction,fluidextraction,densegasextraction,etc.)•LiquidmembraneextractionultrasonicandmicrowaveextractionComplexometricextraction72020/3/23Liquid-liquidextractioncanbesubdividedinto:•Solventextraction(ororganicsolventextraction)•Two-phaseaqueousextraction(oraqueoustwo-phasepartitioning)(双水相萃取）•ReverseMicellesExtraction82020/3/23AdvantagesDisadvantagesOrganicsolventsarevolatilethanwaterOrganicsolventenvironmentscandenatureproteinsandbiomoleculesCrystallizationmayproducelarger,purercrystalsFlammabilitycanbecomeanissueInorganicsaltsaremostlyleftbehindintheaqueousphaseToxicityrisksandhazardouswastedisposalcostsmustbeassessedAdvantagesandDisadvantagesoforganicsolventextraction92020/3/235.1.4Two-phaseaqueousextraction1.DefinitionTheadditionofoneortwowater-solublepolymersalongwithamineralsaltcancausetwoorthreedistinctphasestoform(incompatibility).Thesephaseswilltypicallycontain80%to90%water.Thus,theextractionusingthisenvironmentprovidedbytheseaqueousphasesarecalled“two-phaseaqueousextraction”.一到两种水溶性聚合物的水溶液，或一种水溶性聚合物水溶液与无机盐溶液混合时可形成不相容而有明显界面的两到三相系统（通常含水80%~90%），以此系统进行的萃取谓之“双水相萃取”。102020/3/23Mostcommonlyusedpolymers:PEG/DextranPolymerandahighconcentrationofsalt:PEG/PhosphateorPEG/Sulphate聚丙二醇(PPG)聚乙二醇(PEG)聚乙烯醇(PVA)葡聚糖(Dex)聚蔗糖(Ficoll)羟丙基葡聚糖A聚乙二醇(PEG)聚乙烯醇(PVA)葡聚糖(Dex)聚乙烯吡咯烷酮B硫酸葡聚糖酸钠羧甲基葡聚糖酸钠聚丙烯乙二醇甲基纤维素C羧甲基葡聚糖酸钠羧甲基纤维素钠盐D聚乙二醇硫酸钾，硫酸铵，硫酸钠，硫酸镁，磷酸盐酒石酸钠琥珀酸钠，柠檬酸纳E聚乙二醇葡聚糖乙二醇单丁酯丙醇112020/3/232.Characteristicsoftwo-phaseaqueousextraction(1)Theenvironmentorconditionprovidedbyaqueousphasesisgentlerthanthatofsolventextraction,whichcankeepthetargetproductsfromdenaturationorinactivation.萃取环境、条件温和，产物不易失活(3)Goodbiocompatibility生物相容性好，有时有稳定作用(4)Thepartitioncoefficientiscontrolledreadily分配系数可控制，如聚合物修饰、相系统组成、操作条件容易放大，可达几百倍。⑵lowinterfacialtension,onlyabout0.5-10-4mN/m界面张力小，一般只有0.5-10-4mN/m122020/3/23(1)Typesoftwo-phaseaqueoussystemscommonlyused(i)polymers/polymers:PEG/Dextran(ii)polymers/low-molecule-weightmaterials:e.g.,PEG/phosphate3.Two-phaseaqueoussystems132020/3/23(2)PhasediagramsleverrulephasediagramdrawingHighpolymerBhighpolymerACloudyphase1Adding1mlH2O2AddingMTMDVVDT(highpolymerA)TMDCMassfactionofhighpolymerA/%MassfactionofhighpolymerB/%binodaltielinehighpolymerA-Btwo-phaseaqueoussystemBackto5.2142020/3/235.2extractionprinciples5.2.1ChemicalThermodynamicsofPartitioningAtequilibrium,eachcomponentinasolutionhasthesamechemicalpotential:12Then:01110222lnlnRTaRTa002112RTayeaxactivity(活度)152020/3/23Definethepartitioncoefficient(分配系数)Kas:002112RTayKeaxIndilutesolutionandataconstanttemperature:0021RTyKex5.2.2SelectivityInordertoindicatetheeffectivenessoftheextractioninpreferentiallyselectingonesoluteoveranother,theselectivityisdefinedasfollows:1'2'112122//ccKccKFornormalextraction,12mustbelargethan1c:molefraction162020/3/23Howabout?1215.2.3FactorsaffectingpartitioncoefficientThepartitioncoefficientcandependonmanyparameters:thesizeofthemoleculebeingextracted,pH,typesofsolvent,temperature,concentrationaswellasmolecularweightofpolymers(orsalt)inthephaseandsoon.1.Moleculesize172020/3/23K182020/3/232.pH192020/3/2300.20.40.60.866.577.588.59pHKpH对磷酸化酶的分配系数的影响相系统：7.2%PEG4000/6.7%DexT500,200mM缓冲液◆PO43-■Tris在PEG/Dex系统中，当使用Tris缓冲液时，在pH7-8.5范围内，不会使缓冲离子的电荷发生改变，对酶的分配系数影响不大；而在使用磷酸盐缓冲液时，改变pH对缓冲离子的电荷数及其不同离子的比例影响很大，而此时酶分配系数发生明显改变。202020/3/230510154.55.56.57.58.5pHKpH对L-2-羟基异己酸脱氢酶的分配系数的影响相系统：18%PEG/7.0%磷酸钾●PEG1540■PEG4000◆PEG6000▲PEG10000在PEG/盐系统中，pH变化对酶的分配系数的影响更大，并且这种影响因PEG的分子量的不同也