生物加工过程Issue(6)：30-35,6.DOI:10.3969/j.issn.1672-3678.2015.06.006
β半乳糖苷酶的筛选、克隆表达、酶学性质及其酶法合成低聚半乳糖
Screening,cloning,expression,characterization of β-galactosidase and enzymatic synthesis of galacto-oligosaccharides
摘要
Abstract
Strains were screened from organic solvent tolerant bacteria, though the hydrolysis of o⁃nitrophenyl⁃β⁃D⁃galactopyranoside (oNPG).After rescreened by lactose as using lactose as substrate,strain Erwinia billingiae WX1 showed high transgalactosidation. Based on the nucleotide sequence of the β⁃galactosidase from Erwinia billingiae,the gene encoding theβ⁃galactosidase GAL was cloned and expressed in Escherichia coli. The gene consists of 1 428 bp,and the translated protein encodes 475 amino acids and its molecular mass is approximately 5�2×104. After purification,the purity of this enzyme showed that the optimal pH and temperature were 7�0 and 55 ℃,respectively. Its activity was notably promoted by Mg2+, Mn2+,whereas EDTA had high inhibition to the enzyme. The enzyme synthesis of galacto⁃oligosachorides was studied by using its transgalactosylation. The optimum synthesis condition of galacto⁃oligosachorides was as follows:400 g/L lactose,1�0 Uβ⁃galactosidase GAL,reaction with temperature 40℃ for 16 h,under the conditons, the production rate of galacto⁃oligosachorides was 34%. Our findings demonstrate that the recombinant β⁃galactosidase has good development prospects.关键词
Erwinia billingiae/β半乳糖苷酶/克隆表达/酶法合成/低聚半乳糖Key words
Erwinia billingiae/β-galactosidase/cloning expression/enzymatic synthesis/galacto-oligosachorides分类
生物科学引用本文复制引用
王欣,吴斌,何冰芳..β半乳糖苷酶的筛选、克隆表达、酶学性质及其酶法合成低聚半乳糖[J].生物加工过程,2015,(6):30-35,6.基金项目
高等学校博士学科点专项基金（20123221130001）；国家自然科学基金 （）
