ENZYME IMMOBILIZATION 固定酶文档格式.docx
- 文档编号:19198969
- 上传时间:2023-01-04
- 格式:DOCX
- 页数:13
- 大小:816.40KB
ENZYME IMMOBILIZATION 固定酶文档格式.docx
《ENZYME IMMOBILIZATION 固定酶文档格式.docx》由会员分享,可在线阅读,更多相关《ENZYME IMMOBILIZATION 固定酶文档格式.docx(13页珍藏版)》请在冰豆网上搜索。
Partners:
WuTing,WangTing,ZhouHan,WayneTravers,SanhanathMeadows
Date:
7th,21stOct
Abstract:
TheeffectofdifferentconditionsoffermenterslikeairflowandagitationspeedontheantimicrobialactivityofS.Warneribacteriocinswerestudiedinthisexperiment.Thebestconditionsweredeterminedbyantimicrobialactivitywhichdecidedbythezonesizeandhighestdilutiondemonstratingactivityofthebacteriocinsafterdifferentperiods.Theexperimenthasbeendonefor2weeks.10differentconditionshavebeentested.Thehighestairflow(4L/min)andagitationspeed(450RPM)weredecidedastheoptimizedoperatingcondition.
Andtheconcentrationofdissolvedoxygenandturbiditywerealsostudiedbythecurve.
Introduction/Background
Bacteriocinareantibioticpolypeptide,proteinorproteincomplexproducedbysomebacteria.In1982,Konislydefiniteditastheproteinwhichhasantimicrobialactivitiesgeneratedbytheribosomesofsomebacteria.Generally,mostofbacteriocinswillonlybetoxictothebacteriahavingclosegeneticrelationship.SourcesofbacterioncinsareverywidelikeGram-positivebacteria(G+)(E-coli),Gram-negativebacteria(G-),andarchaea.ThebacteriocinproducedbyLacticacidbacterialikenisinhashighgradeofsafetywhichhavebeengenerallyappliedatfood,pharmaceuticalindustrybecauseofthegreatpotentialoftheproducedbacteriocinsasfoodadditives.Inrecentyears,otherbacteriocinslikebacteriocinsproducedbystaphylococcalspecieshavebeenstudiedmoreandmore.Staphylococcusbacteriocinshavemanyadvantagessuchasdifficulttohavebacterialresistance,noresidue,non-toxicsideeffectsonbodyetc.ItismeaningfultotreattheinfectioncausedbyStaphylococus.
Differencebetweenantibioticsandbacteriocins.
Somearticlesdidn’tseparatedtheantibioticsandbacteriocins.Itwilllimitedtheappropriateapplicationofbacteriocinsinfoodindustry.Althoughtheyarebothproducedbymicroorganisms,therearemanydifferenceontheproductionmethodsandmechanismsofactionetc.1.Bacteriocinsareprimarymicrobialproductsynthesizedbyribosomeswhichbelongingtoproteinswhiletheantibioticsaresecondarymicrobialproductsynthesizedbymultienzymecomplexes.2.Inaddition,bacteriocinshaverelativelynarrowantibacterialspectrumwhichonlyaffectthebacteriahavingclosegeneticrelationshipwhiletheantibioticshavewideantibacterialspectrum.3.Antibioticsareappliedontheclinicaltherapywhilethebacteriocinsareappliedonfoodindustry.
Themechanismofactionofbacteriocins:
Bacteriocinsabsorbedtothecellsurfacenon-specificallybutthespecificbindingwithcellisdependedonthestructureofthecellwallandplasmamembrane.TheabsorptioncapacityofG-positivebacteriocinsisrelativeweak,maynotneedtocombinewithspecificreceptorandcanaffectdirectly.ComparedwithG-positivebacteriocins,G-negativebacteriocinsshouldcombinefirstlybelongingtoreceptor-mediateabsorption.G-positivebacteriocinsdestroythestructureofmembranebyformingamembranechannelontheplasmamembraneofsusceptiblecelloraffectsthestabilitywhichleadstocelldeathbytheleakageofions,aminoacids,andATP.DifferentG-positivebacteriocinsneeddifferentminimummembranepotentialtoreact.Inadditiontoformafilmchannel,someG-positivebacteriocinscanalsoinducecellautolysis.Actually,itissimilartomostofantibioticsinsomeways.
Theusageofbacteriocins
Becausebacteriocinshavemanyadvantagessuchashighefficiency,widerangeofapplication,nochangetotheflavorofproduct(goodadditives)andpathogenresistance.Sobacteriocinshavebeenappliedtofood,medicine,andfodderetc.
Infoodindustry:
Nisinhasbeenusedasimportantnaturalfoodpreservativeinworld.Itmainapplicationareasincludemilkproducts(includingfreshmilk,powderedmilk,yogurt,cheese,etc.),cannedfood,beverage,meat,fish,andalcoholicbeveragesetc.Bacteriocinsoftencombinewithotherpreservationmethodandcangreatlyimprovetheeffectivenessofpreservative.Severalfactorsneedtobeconsideredbeforeaddingbacteriocins.Firstly,thestructureandcompositionoffoodneedtobeestimatedbecausethespecificcomponentcanaffecttheactivityofbacteriocins.Forexample,bacteriocinscanbondwithfattoaffectitsactivity.Secondly,temperature,pHandexogenousenzymes(eg.Proteases)shouldalsobeconsidered.Bacteriocinscanbebyproductsoffermentationpresentedincheese,yogurt,sausage.Itcanpreventandcontrolthecontaminationcausedbybacteria.
Inmedicine:
Duetothegrowingproblemofantibioticresistance,peopleconstantlylookingforsomethingthatcanreplacetheantibiotics.,whichbacteriocinshavebeenconsideredtohavegreatpotentials.Comparedwiththewideantibacterialspectrumofantibiotics,thebacteriocins’antibacterialspectrumisnarrow,withsomespecificity.Butitisdifficulttohavedrugresistance.Atthesametime,thespeciesofbacteriocinsaremorethanantibioticsandpeoplenormallyabletofindtherelativelybacteriocinforanykindofbacterialpathogens.Currently,thetreatmentofbacterialinfectionsusedbacteriocinsaregenerallyappliedproducingbacterialstrains.Noneofbacteriocinshasbeenusedasdrugforclinicaltreatmentdirectly,butonlyappliedinlaboratory.
Bacteriocinshavegreatpotentialincommercialproduction.Butforlarge-scaleproductionofbacteriocins,currentlytherearemanylimitations.Firstly,althoughthebacterioinshavemanyspecies,onlynisinhasbeenusedasacommodity.Secondly,thecurrentapplicationofnisinstillhasmanydifficult.1)mostofthelacticacidbacteriahasnarrowspectrum.2)Theamountofbacteriocinsarealittle.
Method
Oct7th
1.Prepared4agarplates(useTSA)
TSAquantity:
40gfor1L→2.4fgfor60ml
Put2.4gTSAand60mlintotube→4x60ml
1.Putthemintoautoclavetosterile(hightemp.andhighpressure)
2.Oncesterile,prepareGroassayplates→Add1.2mlofa50:
50mixtureoftween20waterand3mlofafreshlygrownbroth
3.Shakedthetubeuntilitisnotveryhot.
4.Pouredthecontentsintoa150mmsterilePetridish.
5.Allowedthecontentsoftheplatetosolidify.
6.Asepticallycutaseriesofwellsintheagarplateusing0.5mlvolumes.
Thegraphofinoculation.
7.PreparedasetofserialdilutionsofthesamplesusingTSB→6microtubescontaining250ulTSB/timept
8.AT13:
00,14:
00,15:
00,16:
00Repeatthefollowingsteps
preparesample→centrifugedandfilteredit.
Dilutedthesampleinto6sixtubesandmarkedthemfrom1to6
Took250ulneatintothefirsttubeandcentrifugeditfollowedbytaking250ulfromthefirsttubeintothesecondtube.Andsoon.
Usingpipettetoplace100ulofsample(neat),nisin(aspositive),broth(asnegative),andaseriesofdilutionintowells.
Positivetestifthereisbacteria
Negativetestifthereiscontamination
Oct21st
TheprocedureissameastheOct7th.
Discussion
∙QUAD3:
07/10/2014pH7.0,300RPM.37℃,2L/min
PHandtemperature:
ThepHandtemperaturehadbeenmaintainallthetime.
Turbidityandoxygen:
1.Thegraphshowsthatduringthefirst1h,theturbidityclimbedslowlyfromalmost0AUto0.2Authan1h-5h.whilethepO2wasdecreasingsteadilyfrom90to80between0hand1h.→Itmaymeanthatthebacteriawasinlagphase,andoxygenwasconsumed
2.Between1hand5htheturbidityclimbedrapidlyfromalmost0.4Auto1.8Auwhendissolvedoxygendroppeddramaticallyatfirstfrom1hto2.5h.→Itmaymeansthatatearlyexponentialphase,thenumberofbacteriawasincreasingrapidlyandtheoxygenuptakerateofthebacteriawassignificanthigherthantherateoffermentersupport.
3.Between1hand5htheturbidityclimbedrapidlyfromalmost0.4Auto1.8Au,whendissolvedoxygenreachedequilibriumfrom2.5hto5handhadremainedstableatalowlevel.→Itmeansthatwhenthebacteriawasduringtheexponentialphase(1h-5h),thenumberofbacteriawasincreasingrapidlyandbacteriagrowthrequiredalotofdissolvedoxygen.
Inthefermentationprocess,whenthedissolvedoxygenintheculturemedium(CL)washigherthanthecriticaloxygenneededbycellgrowth,metabolicactivitiesandrespirationofcell,therateofgrowthwasn’taffectedandbacteriagrowthrequiresalotofdissolvedoxygen.
4.After5h,turbiditygrowslowlyandsteadilyfrom1.8Auto2.2Auwhenthedissolvedoxygentrenddidn’tchange.→Itmaymeanthatbacteriawasduringthedecelerationandstationaryphase,alotofthedissolvedoxygenwasrequiredbybacteriagrowth.
∙QUAD2:
21/10/2014pH7.0,300RPM,37℃,4L/min
PHandtemperature:
Turbidityandoxygen:
1.Thegraphshowsthatbetween0hand3h,theturbidityslightlyroseandthepO2slightlydecreased.→Itmaymeanthatthebacteriawasduringthelagphaseanditneededoxygen.
2.Between3hto12h,theturbiditygrewrapidlyfromalmost0AUto2.6AUandthepO2increasedrapidlyduring3h-4h,thenthecurvebecamesteady.→Itmaymeanthatthebacteriawasinexponentialphaseandneededalotofoxygenatfirstbutafter4h,thegrowthtrendwassteadyandpO2didn’taffecttherateanymore.
3.Between12hand20h,theturbiditywerebothsteadyandthepO2wasfluctuatedslightly.→Itmeansthatthebacteriawasindecelerationandstationaryphase.
4.Between20hand24h,theturbiditydroppedalittlewhenthepO2didn’tchange.→Itmayrepresentthatthebacteriawasinthedeathordecline
- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- ENZYME IMMOBILIZATION 固定酶 固定