从生物量生产丙烯酸的研究和开发进展

1、从生物量生产丙烯酸的研究和开发进展ChineseChem.Eng.,14(4)4l9_427(2006)REVIEWSAdvancesintheResearchandDevelopmentofAcrylicAcidProductionfromBiomassxuXiaobo(许晓波),LINJianping(林建平)andCENPeilin(岑沛霖)料InstituteofBioengineering,ZhejiangUniversity,Hangzhou310027,ChinaAbstractTheshortageofpetroleumhasresultedinworIdwideefforts

2、toproducechemicalsfromrenewablere.sources.Amongtheseattempts,thepossibihtyofproducingacrylicacidfrombiomasshascaughttheeyeofmanyresearchers.Convertingthecarbohydratesfirsttolacticacidbyfermentationandthendehydratinglacticacidtoacrylicacidishithertothemosteffectivewayforproducingacrylicacidfrombiomas

3、s.lethelacticacidfer-mentationhasbeencommercializedsincelongertimes,thedehydrationprocessoflacticacidisstillunderdeve1.opmentbecauseofitslowyield.Furthereffortsshouldbemadebeforethisprocessbecameeconomicallyfeasible.Becauseoftheexistenceofacrylicacidpathwaysinsomemicroorganisms.strainimprovementandm

4、etabolicen.gineeringprovidesalsoapossibilitytoproduceacrylicaciddirectlyfrombiomassbyfermentation.Keywordsrenewableresource,acrylicacid,biomass,lacticacidlINIRoDUCTIoNEnergyresourcesaredividedintotwocategories:renewableandnon-renewable.Thefossilenergyre-sources,suchaspetroleum,coal,naturalgasandnu-c

5、learenergy,arenonrenewable,whereassolarenergy,hydraulicenergy,windpoweraswellasbiomass,etc.,arerenewable,Nowadays,worldwideeffortstoreduceatmosphericCO2emissionsandtoovercometheshortageandsharppriceriseoffossilenergyresources,especiallypetroleum,simultaneouslytriggerresearchonbiomass-basedtechnologi

6、es.Renewableresourceshavebeguntobecomeapopularphrase.Therenewableresourcesareinexhaustibleandclean,amongwhich,biomassisofparticularimpor-tance.Biomassistheproductofphotosynthesisofplantsandmicroorganismsthatisproducedinhugequantitieseveryyear.Themajorityofbiomassishy-drocarbons,suchasstarch,semi-cel

7、luloseandcellu-lose,whichcanbehydrolyzedintofermentablesugars,mainlyglucoseandxylose.Fromfermentablesugars,variousproductscanbeproducedbymicrobialproc-esses,suchasethanol,organicacids,aminoacids,enzymes,antibiotics,etc.Amongthem,ethanolandlacticacidareofspecialimportance.Ethanolhasbeenusedasgasoline

8、additiveformanyyearsinvariouscountries【andhasbecometherawmaterialforeth.yleneproduction.Traditionally,lacticacidisusedinf0odindustry,butthesuccessfulsynthesisofbiode-gradablepolylacticacidopensnewopportunityforlacticacidfermentation.Comparedwithethanolfermentation,lacticacidfermentationhasthedistin.

9、guishedadvantageofhighproductivity.Whenglucoseisusedassubstrate.thetIleoreticalandpracticaletIla.nolyieldsine山anolfermentationareonly0.5land0.440.47g?g-1(ethanolglucose),whereas1.0and0.90_.94g?g(1acticacidglucose)canbeobtainedinlacticacidfermentation.respectively.Therefore,lacticacidfermentationisan

10、atomic.savingprocess.Acrylicacidanditsesterderivativesareprincipalrawmaterialsinthemanufactureofpolymericprod.ucts.Thepolymersmadeofacrylicacidanditsde.rivativesarecharacterizedbycolorlesstransparency,easyadhesion,elasticity,andstabilitytolight,moder-ateheataswellasweatIlering.AndtIleyarewidelyappli

11、edinsurfacecoatings,textiles,adhesives,papertreatment,polishes,leather,fibers,detergents,andsuper-absorbentmaterials.etc.j.Currently.allacrylicacidisproducedfrompetrochemicalindustrybytwo?-stepgas?-phaseoxidationofpropyleneandthetotalworldwideproductivityismorethan3milliontonsperyear【oj.Highpriceofc

12、rudeoilpromotestheresearchanddevelopmentofacrylicacidproductionfromnewrawmaterialswithnewtechnology,inwhich,thedehydrationoflacticacidforacrylicacidproductionisacompetitiveprocessandhasattractedmanyscientistsandengineerstodevelopnewproc-Received2005-0719,accepted200603-31.SupportedbytheSpecialFundsf

13、orMajorStateBasicResearchProgramofChina(973Program,No.2004CCA05500)Towhomcorrespondenceshouldbeaddressed.Email:cenpl420ChineseJ.Ch.E.(Vo1.14,No.4)eSSes.Inthisarticle.therecentadvancesintheresearchanddevelopmentoflacticacidfermentationarereviewed.Then,thedehydrationmethodsoflacticacidforacrylicacidpr

14、oductionareintroduced.Finally,theprospectofacrylicacidproductionfrombiomassisdiscussed.2LACTICACIDFERMENrATIoNANDSEPARALTIoN2.1LacticacidfermentationThecommercialproductionoflacticacidbyfermentationwasstartedattheendofthe19thcentury【J.soitisconsideredasoneofthefirstbiotechnologicalprocessesoperatedu

15、ndercontrolledconditions.Itispossibletodistinguishthelacticacidfe卜mentationashomoandheterolacticacidtypes.功eexistingcommercialproductionprocessesusehomolacticorganisms,suchasLactobacillusdelbriickii,L.bulgaricus,L.1eichmannii,exceptRhizopusoryzae9】forL.1acticacidproductionv/ahetero.1acticacidpathway

16、.LacticacidisoneofthesmallestchiralmoleculeswithD一,LisomersandracemicDL-lacticacid.Thechemicallysynthesizedlacticacidisracemic,whereaswjthdifferentstrains.thefermentationproductcanbeD一.L_orDL-lacticacid.MicroorganismsforlacticacidproductionandtheirpropertiesarelistedinTable1.Thefermentationtechnolog

17、ycanproduceadesiredstereoisomeroflacticacidortheracematewhenaspecificstrainisused.Awidevarietyofcarbohydratesources,suchasmolasses,starchhydrolytes,whey,dextrose,caneorbeetsugar【J,orevenhydrolytesoflignoceUulosicmaterials.callbeusedasfeedstocks.MostoflacticacidproducingstrainsCallbecultivatedanaerob

18、ically,exceptRhizopusoryzae,whichmustbeculturedaerobically.Theadvantagesofanaerobicfermentationincludelowinvestmentandlowenergyconsumption.Generally,thetheoreticalyieldoflacticacid.whenglucoseisusedascarbonsource.is100%,whereasthepracticeyieldoflacticacidisapproximately90%(bymass)inananaerobicfermen

19、tationprocess.Thelactatemassconcentrationinthefennentationbrothcanreach10%一13%.Inclassicindustrialbioprocesses,alkalisuchasNaOH,CaCOandNHmustbeaddedtothebrothtomaintainalowfreelacticacidconcentrationinordertopreventtheinhibitionofbacteria.Howevehtheiradditionmakesthepurificationprocessdifficultandth

20、ishasgreatenvironmentalimpact.Apartfromtreatmentwithalkali,varioustech.niquescombiningfermentationprocesswithsimultaneousproductseparationhavebeenproposedtocontinuouslyremovethelacticacidasitisformed.AmeanstoovercometheproductinhibitionisinsituproductremovalrISPR)suchasextractivefermen.tation一剐,adso

21、rptionfermentation一加】.membranefle彻entation一.Reactiveextractionwithspecifiedextractantgivingahigherdistributioncoefficienthasbeenproposedasapromisingtechniquefortherecoveryoflacticacid.Reactiveliquid-liquidextractionhastheadvantageofeasyremovaloflacticacidfromthefermentationbroth,therebypreventingthe

22、loweringofTable1Microorganismsforlacticacidproductionandtheirproperties忉Note:LAlactacid;AAaceticacid.August,2006AdvancesintheResearchandDevelopmentofAcrylicAcidProductionfromBiomasspH,.1kextractionprocessdoesnotaffectthethermalstabilityofbioproducts,andtheenergyde-mandissubstantiallylow.Inthismethod

23、,theamineinthesolventphasereactswiththelacticacidintheaqueousphase,resultingintheextractionofacidintotheorganicphase.Theapplicabilityofdifferenttypesoforganiccarriersanddiluentshasextensivelybeeninvestigatedb.Secondaryandtertiarylong.chainalkylamineshavebeenfoundtopromotetheextractionefficiencyandse

24、lectivity.andalcoholsareamongthebestdiluents【26.ButthesolventsusedinISPRaretoxicastheyrupturethecellmembranecausingthemetabolitetoleakout.Long-chainalco-holssuchas1.octanoland1.decanolarefoundtobelesstoxicthanotherdiluents.Adsorptionfermentationprocesshasbeenstud-iedwhereinpHvalueisregulatedbytheads

25、orptionoflacticacid.Asanefficientabsorbent,ionexchangeresiniswidelyusedinbioseparationandseveraldif-ferentionexchangers【720havebeenusedforlactateseparationinthelastfewyears.Thistechniqueiscompetitivebecauseofitshighselectivity,highex-changecapacityandsimpleoperation.Membranebioreactorcombinestheferm

26、entationprocesswiththesimultaneousproductseparation.Tl1elacticacidiscontinuouslyremovedfromthemembraneasitisformed.sohighcelldensityisobtained.whichresultsinhigherproductivity.Differentmembranes,suchaselectrodialysisI2l.hoHowfiberultrafiltrationmembrane【.reverseosmosismembrane22,24areusedinthecel1.r

27、ecycle.VishalShaheta1.t圳haveachievedamaximumcelldensityof145g.dm一andamaximumproductivityof34g?dIIl-3.hincell-recyclefermenta-tion.Inthismethod.1acticacidfermentationisinves.tigatedinacel1.recyclemembranebioreactorwithasubstrateconcentrationashighas120g?dm.Fed.batchprocessisalsousedinlacticacidfer.me

28、ntationtoavoidsubstrateinhibitionLJ.AccordingtotheworkreportedbyBaieta1.,upto210g?LL.1acticacidwasobtainedandtheaverageLlacticlactatesaltinfe:rmentationbrothacidificationacticacidesterificationanddistillationlactateester421acidproductivitywas2.2g.L-1.hinafed.batchfer-mentationofL以cZDcctis291.2.2Sepa

29、rationandpurificationoflacticacidTheeconomicsofthefermentationprocessde.pendonthedevelopmentofaneffectiverecoverymethodforlacticacidfrombroth.becausethesepara.tionandpurificationstepsaccountforupt050%Oftheproductioncosts3.Althoughthedifferenceinboilingpointbetweenlacticacidandwaterisquitelarge,itisa

30、lmostimpossibletoobtainpurelacticacidcrysta1.Thereasonsarethatlacticacidhashighlyaf-finitytowaterandlactatedimmerwillbeformedwhentheconcentrationoflacticacidishighenough.Thecommercialproductoflacticacidisgenerallyanaqueoussolutionwith85%lacticacid.Theseparationandpurificationprocessesoflac.ticacidfr

31、omfermentationbrothareshowninFig.1.Tl1ecalciumlactatesolutioniscrystallizedandcon.vertedintolacticacidbyaddingsulphuricacid.Inthisbioprocesses,extractioniscarriedoutthroughprecipitationstageswhichproducelargequantitiesofgypsum(calciumsulfate)thathavetobetreatedaswasteTM.Overthepastfewdecades.1otsofi

32、mprovementshavebeenmadetoreducethehighproductrecoverycostandtheenvironmentalimpact.Manystudiesconcerninglacticacidseparationhavebeenconductedusingdifferentseparationtechniques,suchasreactiveextraction,membraneseparation,ionexchange,elec-trodialysis.chemicalreactiondistillationIl81.andre.verseosmosis

33、.Eachoftheseexhibitssomeadvan.tagesanddisadvantagesthatarealsodescribedwithfermentationprocessesearlierinthisreview.Analternativeprocessistoformlactices.ter【3235.suchasmethyllactate,thenpurifylactateesterbydistillation.Thelactateestermustbehydro.1yzedtoobtainfreelacticacidandmethano1.Metha.nolandlit

34、tleamountofwatercanberemovedbydistillatiOn.MaPt,.【36,37havesetupawholeprocesstovacuumevaporationormoleculardistillationhydrolyzation85%lacticaciddistillationlacticacidandmethanoFigure1SeparationandpurificationprocessesoflacticacidfromfermentationbrothChineseJ.Ch.E.14(4)419(2006)ChineseJ.Ch.E.(Vo1.14

35、,No.4)purifylacticacidbyesterificationcouplingcatalyticdistillation.Thisnoveltechnologyhasconsiderableprospectsbecauseofitslowenergyconsumptionandlowinvestment.Acompletedrecoveryandpurificationprocessinvolvingelectromembraneoperationshasbeenreported3B1.Itincludesbrothclarificationbycrossflowfiltrati

36、on39,401,treatmentbychelatingresins,concentrationoflactatesaltsintofreeacidbybipolarmembraneelectrodialysisandionexchangetreatment.3DEHYDRATIoNOlFLACTICACmToPRODUCEACRYLATESVIACHEMICALREACTIONThereisahydroxylandacarboxylgroupinlacticacidmolecule;therefore,itisconvenienttoconvertlacticacidintovarious

37、valueaddedproducts4.421.suchasacetaldehyde川,acrylicacid,propyleneglycolt441.2,3一pentanedione,andpolylacticacid【451.Fig.2showssomeexamples.Becauseoftheirimportantapplicationsintheproductionofbiodegradablepolymersandothercompounds.lacticacidisregardedasoneofthecommodityorplatformchemicals,inadditionto

38、itstraditionalapplicationinfoodindustry.Amongthesecompounds.theproduIctionofacrylicacidortheiresterisofspecialsignificance.Acrylicacidcanbeproducedbythecatalyticdehydrationoflacticacid.Holmen【4.filedapatentinAugust,2006H0.0lacticaciddecarbonylationwhichthevapor-phaseconversionoflacticacidtoacrylicac

39、idoverseveralkindsofsaltcatalystswasperformedforthefirsttime.AndthemosteffectivecatalystwasthemixtureofCaSO4andNa2SO4witllthemolarratioof25:1.Itcouldgiveacrylicacidyieldof54%whenthelacticacidsolution(10%)passedthepyrolysistubeatl015ml?h一andat400.Sawickireporteda58%acrylicacidyieldat350usingNa2HPOdon

40、silica/aluminaascatalystwithNaHCO3asapHadjuster.Atthesametime.Pa.parizos【4achieved43%acrylicacidyieldat340.thecatalystwasAlPotreatedwithNH3.Intheseprocesses,lowconcentrationlacticacidsolutionwasusedasrawmaterial,whichmeansthatafteracidification,lacticacidinfermentationbrothcanbedirectlyconvertedinto

41、acrylicacidwithoutfurtherprocessing.Itispromisingtodehydratelacticacidforacrylicacidproductioninsupercriticalornear-criticalwater.Moketa1.conductedtheexperimentsat385and34.5MPa.withaninitiallacticacidconcentrationof0.1mo1.L一andaresidencetimeofapproximately30sTheresultindicatedthatdecarbonylationofac

42、etaldehydepredominatedwiththeadditionofH2SO4.Incontrast.moreacrylicacid,carbondioxideandhydrogencouldbeproducedifNaOHwasadded.In1993.PerryandCarlreportedthattheadditionofsmallamount(<0.01mol?L)ofNa2HPO4t0the0.4mo1.L一reactantsolutionwasabletoraisethepHvalueandincreasetheacrylicacidyieldfrom35%decarboxylationdehydrationreductioncondensationself-esterificationOH.0panoicacid02,3-pentanedionedilactide0Figure2Importantchemicalsproducedfromlacticacid【4l】.礅AdvancesintheResearchandDevelopment