摘要
内切菊粉酶可以有效地水解菊粉得到低聚果糖(IOS),低聚果糖是一种水溶性膳食纤维,应用广泛。为了实现内切菊粉酶的高效表达,通过无花果曲霉中的inu2基因,成功在大肠杆菌中重组表达。为提高表达水平,通过使用pel B和omp C代替本身的信号肽序列,来研究不同的信号肽对菊粉内切酶表达的影响。此外,还通过正交试验的方法优化了IOS的催化条件。研究结果表明,用pel B代替本身的信号肽的E.coli INU2-A3的酶活最高,达到75.22 U/mg。在菊粉为150 g/L,纯化的菊粉内切酶为5 U/g菊粉,55℃,p H 4.6,反应24 h时,低聚果糖的收率达到了94.41%,主要的水解产物为DP3-DP7。
Inulooligosaccharides（ IOS） are a kind of water soluble dietary fiber and have wide application.It can be obtained by hydrolyzing inulin with endoinulinase. Endoinulinase gene inu2 was cloned from Aspergillus ficuum and the recombinant was heterogeneously expressed in Escherichia coli BL21（ DE3）.In order to improve the expression level,native signal peptide was substituted with pel B and omp C then effects on endoinulinase production were investigated. Moreover,the condition for IOS production was optimized by orthogonal design.As a consequence,the highest endoinulinase activity was 75. 22 U / mg by E. coli INU2-A3,with replacement of pel B as its signal peptide.After 24 h under optimal conditions,of 150 g / L inulin,enzyme concentration of 5 U / g inulin,55 ℃ and p H 4. 6,the IOS yield was 94. 41%. The hydrolysis products of the inulin were mainly IOS with DP3-DP7.
出处
《生物加工过程》
CAS
2016年第5期45-50,共6页
Chinese Journal of Bioprocess Engineering
基金
国家自然科学基金(21390200)
江苏高校优势学科建设工程
关键词
内切菊粉酶
信号肽
大肠杆菌
低聚果糖
endoinulinase
signal peptide
Escherichia coli
inulooligosaccharides
