β-半乳糖苷酶酶学性质及其在低聚半乳糖合成中的应用  

Application of β-galactosidase for the synthesis of galactooligosaccharides

作　　者：邢肖肖[1] 齐崴[1] 王梦凡[1] 尤生萍[1] 苏荣欣[1] 何志敏[1] 

机构地区：[1]天津大学化工学院化学工程研究所,天津300072

出　　处：《生物加工过程》2015年第2期30-34,共5页Chinese Journal of Bioprocess Engineering

基　　金：国家自然科学基金(21206113;20976125)

摘　　要：研究乳酸克鲁维酵母所产β-半乳糖苷酶的酶学性质及低聚半乳糖(galactooligosaccharides,GOS)的酶法合成条件。利用高效液相色谱法进行检测,以GOS(聚合度n>3)生成量为指标,考察温度、pH、金属离子种类和浓度对酶活性的影响,以及K+存在时,底物浓度、反应时间、加酶量对乳糖转化率及GOS生成浓度的影响。结果表明:一价离子对β-半乳糖苷酶转糖苷活性具有促进作用,其中K+、NH+4对水解活性同样起促进作用,而Na+起抑制作用;制备低聚半乳糖的最佳工艺条件为37℃、pH8.0、K+0.08mol/L、初始乳糖质量浓度500g/L、反应时间5h、加酶量10μL/g乳糖,此条件下低聚半乳糖的生成质量浓度达到94.74g/L。The properties of β-galactosidase from Kluyveromyces lactis and the enzymatic synthesis of galactooligosaccharides（GOS） were investigated.GOS（degree of polymerization n 3） concentration was analyzed by high performance liquid chromatography（HPLC） and used as experimental index.The influences of temperature,pH,and the type and concentration of metal ions on β-galactosidase activity were evaluated.In addition,the effects of lactose concentration,reaction time and enzyme loading on the formed GOS concentration were optimized in the presence of K＋.K＋and NH＋4 could activate transglycosidase and β-galactosidase.However,Na＋could activate transglycosidase and inhibit hydrolase activity.Furthermore,the optimal conditions for enzymatic synthesis of GOS were determined as 37 ℃,pH 8,0.08 mol/L of K＋,intial lactose concentration of 500 g /L,and the enzyme concentration of 10μL /g lactose.Under these conditions,the maximum GOS concentration reached 94.74 g /L after 5 h.

关 键 词：Β-半乳糖苷酶 乳酸克鲁维酵母 低聚半乳糖 

分 类 号：TS245.6[轻工技术与工程—制糖工程]