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1、第13章氨基酸生产工艺氨基酸是构成蛋白成分目前世界上可用发酵法生产氨基酸有20多种。IntroductionHistoryofaminoacidsproduction:Thestoryofstartedin1908Isolatedglutamicacid,delicioustasteScreenforamino-acid-excretingmicroorganisms:Corynebacteriumglutamicum,In1957.Monosodiumglutamate(谷氨酸一钠:MSG):Aflavor-enhancingcompou
2、nd(Umami)氨基酸α碳原子分别以共价键连接氢原子、羧基和氨基及侧链。侧链不同,氨基酸的性质不同。氨基酸的用途1.食品工业:强化食品(赖氨酸,苏氨酸,色氨酸于小麦中)增鲜剂:谷氨酸单钠和天冬氨酸苯丙氨酸与天冬氨酸可用于制造低热量二肽甜味剂(α-天冬酰苯丙氨酸甲酯),此产品1981年获FDA批准,现在每年产量已达数万吨。2.饲料工业:甲硫氨酸等必需氨基酸可用于制造动物饲料3.医药工业:多种复合氨基酸制剂可通过输液治疗营养或代谢失调苯丙氨酸与氮芥子气合成的苯丙氨酸氮芥子气对骨髓肿瘤治疗有效,且副作用低。4.化学工业:谷氨基钠作洗涤剂,丙氨酸
3、制造丙氨酸纤维。AminoacidsareusedforavarietyofpurposesFoodIndustry:Flavorenhancer;Sweetener(Glycine)ChemicalIndustry:BuildingblocksofcompoundsPharmaceuticalIndustry:InInfusion;inspecialdietaryfood(essentialaminoacid)Leu,Ile,Lys,Phe,Met,Trp,Val,Thr,Arg,HisAnimalfeedadditive:Feedstu
4、ff;eg.Soybean--methionineThebarrelrepresentsthenutritivevalueofsoybeanmeal,whichisfirstlimitedbyitsmethioninecontent.ProductionmethodsandtoolsClassicalstraindevelopment:Bacteriadonotnormallyexcreteaminoacidsinsignificantamountsbecauseregulatorymechanismscontroltheaminoacid
5、synthesisinaneconomicalway.Agreatnumberofamino-acid-producingbacteriahavebeenderivedbymutagenesisandscreeningprogrammes.ProductionmethodsandtoolsClassicalstraindevelopment:Bacteriadonotnormallyexcreteaminoacidsinsignificantamountsbecauseregulatorymechanismscontroltheaminoa
6、cidsynthesisinaneconomicalway.Agreatnumberofamino-acid-producingbacteriahavebeenderivedbymutagenesisandscreeningprogrammes.ProductionmethodsandtoolsConsecutiveapplication:Undirectedmutagenesis;Selectionforaspecificphenotype(显型);SelectionofthemutantwiththebestAAaccumulation
7、ProductionmethodsandtoolsApplicationofrecombinanttechniques:Torapidlydevelopnewproducersbyincreasinglimitingenzymeactivities;Toanalysemechanismsoffluxcontrol;Tocombinethisknowledgewithclassicallyobtainedstrainsfortheirfurtherdevelopment氨基酸的生产方法发酵法:直接发酵法:野生菌株发酵、营养缺陷型突变发酵、抗氨
8、基酸结构类似物突变株发酵、抗氨基酸结构类似物突变株的营养缺陷型菌株发酵和营养缺陷型回复突变株发酵。添加前体法酶法:利用微生物细胞或微生物产生的酶来制造氨基酸。提取法:蛋白质水解,