鏈霉菌高產(chǎn)木聚糖酶及其酶學性質的研究.pdf

1、中國農(nóng)業(yè)大學博士學位論文鏈霉菌高產(chǎn)木聚糖酶及其酶學性質的研究姓名：丁長河申請學位級別：博士專業(yè)：食品科學指導教師：李里特20030601中國農(nóng)業(yè)火學蹲1。學位論文英文摘婪ABSTRACTMicrobialxylanaseshaveattractedconsiderableresearchinterestinrecentyearsbecausetheirpotentialappIicationinthefoodanimalfeed，pap

2、erandpulpindustriesInthepaper，xylanaseproducingstainswereisolatedfromsoilbyplatescreeningwithxylanasthesolecarbonSOUrCe，andamongthemahighxylanaseproducingstrainwasselectedbyexperimentsinshakeflasksByobservationofitscolon

3、ies，mycelia，spores，andbycomparisonitsphysicochemicalpropertieswithtypicalstain’s(StreptomycescirratusATCCl4699)，itwasidentifiedasStreptomycescirratusD一1oElevenxylanaseproducingimprovedstainswerescreenedbypenicillincontai

4、ningplateaftersporesofStreptomycescirratusD10weretreatedwithUVirradiationandethyl，methanesulfonateTheeffectsofdifferentfactorsonxylanaseproductionbyStreptomycescirratusD10werestudiedinshakeflaskconditionThebestinitialpHv

5、alueofgrowthmediumforxylanaseproductionwasatpH60Corncobxylan(waterinsoluble)andTryptoneWerethebestCandNsourcesrespectivelyTheenzymeactivitywasincreasedtoabout25timesbyadditionofO5％Tween80inthemediumThehighestxylanaseacti

6、vitywasupto623u／mL。AxylanasewasseparatedandpurifiedfromtheculturefiltrateofStreptomycescirratusD一10byammoniumsulphateprecipitationandQsephmseFFionexchangechromatographyThemolecularweightoftheenzymewasestimatedtobe22，0KDa

7、bySDS—PAGEAfteratwosteptreatment，ten—foldpurificationwasobtainedwith24％enzymeactivityrecoveryThepurifiedxytanaseshowsmaximalactivityatpH750Itremains90％activityatpHrangesbetweenpH310andpH980under45“CTheenzymeexhibitsmaxim

8、alactivityat65“Candshowsdesirablethermalstabilityunder50CAt1raMconcentration，EDTAandSDShavelittleinfluenceonthexylanseactivityTheinhibiteffectsofdifferentmetalionsontheenzymeactivityareasfollows：Ag)Pb2、Mn2Ctt2、C02Ba“、M92

9、、Ca“Na、K、Zn“TheonlymetalionwhichcanimprovetheenzymeactivityisFe“Theenzymeshowshigheractivityonoatspeltsxylan(waterinsoluble)，beechwoodxylanandbirchwoodxylan；showsloweractivity0noatspeltsxylan(watersoluble)andleastactivit

10、yonselfmadecomcobxylanandcottonseedhuskxylanTheeffectsofdifferentfactorsonxylanaseproductionbyStreptomycesolivaceoviridisE86werealsostudiedinshakeflaskconditionThebestinitialpHvalueofgrowthmediumforxylanaseproductionwasa