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1、耐低温兼性厌氧蛋白酶产生菌192的筛选、鉴定及酶学性质耐低温兼性厌氧蛋白酶产生菌192的筛选、鉴定及酶学性质摘要:为了提高厌氧水解效率,采用双层平板法筛选出一株耐低温兼性厌氧蛋白酶产生菌192。经形态、生理生化和16SrDNA序列分析鉴定为蜡状芽孑包杆菌(Bacilluscereus),对其产酶条件进行了初步研究。结果表明,该菌的最适生长温度为30°C,生长8〜12h达对数期,初始pH7.5时酶活力最高。蛋白酶最适反应温度为45°C、pH7.0,酶活力最高达39.3U/mLo该酶在50°C以下,pH
2、6・0〜9.0性能稳定。在60°C以上热稳定性很差,70°C保存1h酶活力全部丧失。关键词:兼性厌氧;耐低温蛋白酶;蜡状芽抱杆菌;酶学性质中图分类号:Q93-331;Q556文献标识码:A文章编号:0439-8114(2013)04-0807-04ScreeningandIdentificationofPsychrotolerantandAnaerobicProtease-ProducingStrainandCharacterizationofProteaseCUIGuan-huil,2,XIYan
3、-hual,2,CHENGHui-cail,2,ZHANGLi-pingl,2,HUANGYa-lil,2,MAJin-liangl,3(1.InstituteofBiology,HebeiAcademyofSciences,Shijiazhuang050081,China;2.MainCropsDiseaseofMicrobialControlEngineeringTechnologyReseachCenterinHebeiProvince,Shijiazhuang050081,China;3.C
4、ollegeofLifeSciences,HebeiUniversity,Baoding071002,Hebei,China)Abstract:Inordertoimprovetheefficiencyoftheanaerobichydrolysis,thepsychrotolerantandanaerobicprotease-producingstrain192,wasscreenedusingdouble-platemethod.ThestrainwasidentifiedasBacillusc
5、ereusbasedontheresultsofmorphological,physiological,biochemicaland16SrDNAanalysis・Thenitsoptimalprotease-producingconditionswerestudied.Theresultsshowedthattheoptimumgrowthtemperatureofthisstrainwas30°CanditsenzymeactivitywashighestwhentheinitialpH7.5,
6、after8~12hofgrowth・Theoptimalreactionconditionofthisproteasewas45°CandpH7.0,itsenzymeactivitycouldbeupto39.3U/mL・AttheconditionsofpH6.0〜9.0andlowerthan50°C,theproteasewasstable・Theproteasewasunstableatthetemperaturehigherthan60°C,itwouldcompletelylosea
7、ctiviywhenstoringat70°Cfor1h.Keywords:facultativeanaerobic;psychrotolerantprotease;Bacilluscereus;enzymaticproperties蛋口酶是—类重要Jiff的水解酶,占酶制剂市场的65%以上,除在食品、饲料、添加剂、洗涤、皮革、环保等领域外,在厌氧消化系统中加入蛋口酶,不仅对有机物的去除有作用,而且对厌氧发酵产甲烷也有促进作用[1-3]ojiffRademacher等[4]通过添加多种酶來提高厌氧污
8、泥消化速率。Scheidat等[5]在初沉池污泥中加入蛋口酶、糖化酶和脂肪酶,发现均能明显地提高水解作用。Romano等[6]研究表明,添加水解酶后,沼气产率从0.35L/g增加到0.53L/g,甲烷产率从0.15L/g增加到0.29L/go低温蛋口酶具有低温高催化效率等特性,有着中温、高温蛋白酶无法取代的优越性。因此,从过冬污泥中分离出一株耐低温的兼性厌氧蛋白酶产生菌,并对其生理生化和酶学性质等进行了初步研究,以期为其应用于污水处理及厌氧发酵、提高水解效率和沼气产气