細菌氨肽酶的產(chǎn)酶條件優(yōu)化及應用研究.pdf

1、江南大學碩士學位論文細菌氨肽酶的產(chǎn)酶條件優(yōu)化及應用研究姓名：魏亞娟申請學位級別：碩士專業(yè)：發(fā)酵工程指導教師：田亞平20080301AbstractAbstractThesolubilitythethermostabilityandthenutritionofproteinareobviouslyimprovedafterhydrolysised，butitshydrolysategenerallyappearedbitterandwas

2、limitedinapplicationoffoodAminopeptidasesCanbedebitteringexopeptidasesthatselectivelyreleaseN—terminalhydrophobicaminoacidresiduesfrombitterpolypeptidesInthispaperthefermentationconditions，theenzymepropertiesandtheapplic

3、ationinSPlwereinvestigatedOptimizationsofthefermentationconditionwascardedoutasfollows：Cornstarch409／L，Soybeandregs309／L，K2HP0432169／L，KH2P0400749／LMgS047H2003g／L，NaCI1∥L，COCl2lmL(O1mol／L)，temperature40。C，rotatespeed200r

4、／min，pH75，inoculumsize8％，volume20mL／250mLTheaminopeptidaseactivitywas26856U／mLafteroptimization，whichincreased171timesTheoptimumconditionswereinvestigatedonaminopeptidasein7Ljarfermentorwereanalyzed，theaminopeptidaseacti

5、vityreached1200U／mLAsforaminopeptidaseproducedbyBacillussubtisZj016afteroptimization，thepurificationprocedureofethanolfractionation(20％。40％)wasstudiedonTheactivitywasoptimalatpH85and550CThetemperaturestabilitywas2070(2an

6、dthepHstabilitywas80“100Whileinhibitedbythegelatinandotherchemicals，theenzymeactivitywasnotsignificantlyinfluencedbyGlycerolandpeptoneInhibitedbyseveraldivalentcations(Zn2、Ni2)andEDTAActivatedbyC02111eactivationregionoft

7、heenzymeseemedtohadtwoZn2，andeachsubunithadoneKmoftheaminopeptidaseWasO53mmol／Land‰觚Was19231tmol／L／minThelimitedhydrolysisoptimumconditionsofSPIbyaminopeptidaseandbasicproteaseWasstudiedasfollows：hydrolyzingtemperature50

8、℃，pH85，ratiosofbothenzymes／substrate10000U／g，concentrationofsubstrate609／L，totalhydrolysistime4h，hydrolysisdegreeofprotein25O％anditshydrolysisproductisafewbitterThecomparisonsofbittervalue，distributionofmolecularweight，h

9、ydrophobicvalueandfreeaminoacidbetweenthehydrolysisproductbythesynergetichydrolysisandthehydrolysisproductbybasicprotease：theirtypesofelutionanddistributionandproportionofmolecularweightweredifferentthefomerWaslessthanth

10、elatterinthehydrophobicvalueandasforfreeamnioacid，thefomerwas1610mg／L，andthelaRerwas1250mg／LKeywords：aminopeptidase；Bacillus；fermentationconditionsoptimization；enzymeproperties；soybearlproteinisolate；hydrolysis；debitteri