摘要
为研究乳品中具有应用价值的乳糖酶,以乳糖为唯一碳源,用邻硝基苯酚-β-D-半乳糖苷(ONPG)法,从产乳酸的细菌中筛选出了产乳糖酶活力高的菌株RY237,其活性达4.98 U/m L,鉴定为凝结芽孢杆菌。研究了乳糖酶的酶学性质,该酶最适反应温度和最适p H分别为50℃和6.0。该酶在温度40~50℃具有良好的稳定性;p H5.5~8.0表现稳定,p H7.0出现酶活峰值。金属离子Ca^(2+)、K+、Zn^(2+)、Mn^(2+)、Na+、Mg^(2+)对酶活具有抑制作用,Cu^(2+)对酶活具有完全抑制作用,EDTA对酶活具有激活作用。凝结芽孢杆菌RY237乳糖酶活性高、性能优良,具有应用价值。
A novel lactase-producing bacterium RY237 was selected based on β-galactosidase activity using lactose as sole carbon media,and was identified as Bacillus coagulans RY327. The activity of lactase reached 4.98 U/m L. The optimum temperature and optimum p H of β-galactosidase were 50 ℃ and 6.0,respectively. The enzyme was stable at p H5.5 - 8.0,with peak activity at p H7.0,and it was also stable at 40-50 ℃. The activity of β-galactosidase was inhibited by Ca^2＋,K^＋,Zn^2＋,Mn^2＋,Na^＋,Mg^2＋and completely inhibited by Cu^2＋. Its activity was promoted by ethylene diamine tetraacetic acid（ EDTA）.The high activity,thermostability and p H-stability make this enzyme potentially useful in dairy industry.
出处
《食品工业科技》
CAS
CSCD
北大核心
2017年第14期111-115,共5页
Science and Technology of Food Industry
基金
山东省农业科学院农业科技创新工程(CXGC2017A01和CXGC2016B13)
山东省重点研发计划项目(2016GGH3111)
关键词
凝结芽孢杆菌
分子鉴定
Β-半乳糖苷酶
酶学性质
Bacillus coagulans
molecular identification
β-galactosidase
enzymatic characterization
