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1、現(xiàn)代食品科技ModernFoodScienceandTechnology2010,Vol.26,No.1Rhizopusoryzae產(chǎn)酸性蛋白酶條件及其酶學(xué)性質(zhì)研究李理,鐘曉敏(華南理工大學(xué)輕工與食品學(xué)院,廣東廣州510640)摘要:本文以少孢根霉(Rhizopusoligosporus)為對(duì)照研究了豆豉中的一個(gè)分離菌株米根霉(Rhizopusoryzae)產(chǎn)生酸性蛋白酶的條件及所產(chǎn)蛋白酶的性質(zhì),結(jié)果表明這個(gè)菌株的產(chǎn)酶條件和蛋白酶的性質(zhì)與少孢根霉相比有相似性但也存在一些差異:米根霉在水分含量57%~59%、pH2.5~3.0的酸性介質(zhì)中
2、、28~31℃下培養(yǎng)36h時(shí)產(chǎn)酸性蛋白酶能力最強(qiáng),所分泌的蛋白酶系在pH4.0和pH6.0附近有最強(qiáng)的催化活性,在pH3.0~6.0的范圍內(nèi)有較好的穩(wěn)定性,催化反應(yīng)的最適作用溫度為50℃,它的溫度穩(wěn)定性很差,在50℃保溫30min已完全失活;少孢根霉在水分含量52%~55%、pH2.5~3.0的酸性介質(zhì)中、31℃下培養(yǎng)48h時(shí)產(chǎn)酸性蛋白酶能力最強(qiáng),在35℃條件下培養(yǎng)36h也能產(chǎn)生較高的酶活力,少孢根霉分泌的蛋白酶系在pH3.0和pH6.0附近有最強(qiáng)的催化活性,在pH4.0~6.0范圍內(nèi)很穩(wěn)定,催化反應(yīng)的最適作用溫度可達(dá)55~60℃,但它
3、的溫度穩(wěn)定性較差,在50℃保溫30min,酶活力損失達(dá)到90%,保溫120min酶幾乎完全失活。關(guān)鍵詞:米根霉;少孢根霉;酸性蛋白酶;酶學(xué)性質(zhì)文章編號(hào):1673-9078(2010)1-28-6ProductionandCharacterizationofanAcidProteasesfromRhizopusoryzaeLILi,ZHONGXiao-min(CollegeofLightIndustryandFoodScience,SouthChinaUniversityofTechnology,Guangzhou510640,China
4、)Abstract:ThecultureconditionformaximumyieldofanacidproteasefromRhizopusoryzaeandRhizopusoligosporusandthepropertiesoftheproteasewerestudiedinthisresearch.TheresultsshowedthattheoptimumconditionsformaximumproductionofacidproteasefromRhizopusoryzaegrownonwheatbranwerewate
5、rcontentof57%-59%,pHof2.5-3.0,fermentationtemperatureof28-31℃andtimeof36h.ThebestpHvalueandtemperatureoftheachievedproteasewere4.0-6.0and50℃,respectively.TheproteaseshowedhighpHstabilitywithin3.0-6.0andpoorthermo-stability,whichmightloseitsactivitywhenincubatedat50℃for30
6、min.TheoptimumconditionsformaximumproductionofacidproteasefromRhizopusoligosporusgrownonwheatbranwerewatercontentof52%-55%,pHvalueof2.5-3.0,fermentationtemperatureof31℃for48horfermentationtemperatureof35℃for36h.ThehighestactivityoftheproteasefromRhizopusoligosporuswasobt
7、ainedpH3.0orpH6.0,andtemperatureof55-60℃.ItshowedhighpHstabilityat4.0-6.0,butlowerthermalstabilityat50℃.Itwasfoundthatnearly90%oftheproteaseactivitywaslostwhenincubatedat50℃for30min,.Keywords:Rhizopusoryzae;Rhizopusoligosporu;acidprotease;enzymologicalpropertie天培和豆豉均為發(fā)酵大
8、豆制品。天培(Tempeh)和細(xì)菌型豆豉兩大類,而霉菌型豆豉又分為根霉型、[3]起源于印度尼西亞,是以大豆為原料,經(jīng)脫殼、浸泡、曲霉型和毛霉型。瀏陽豆豉是曲霉型豆豉的典型代蒸煮、接種根霉菌后再經(jīng)短時(shí)間發(fā)酵而