摘要
将来自于Bacillus circulans 251的β-CGTase编码基因克隆到表达载体pET-20b(+),转化Escherichia coli BL21(DE3)。经酶活检测培养基上清中的β-CGTase酶活为20 U/mL。对酶转化淀粉生成β-环糊精的反应条件进行了优化,结果表明,当底物马铃薯淀粉浓度15%,反应初始pH5.5,温度30℃,加酶量10 U/g干淀粉,环己烷浓度2.5%-5%(V/V),转化周期24 h,β-环糊精转化率达到最高值75.3%,是国内外报道的酶法生产β-环糊精的最高水平。
The βcgt gene encodingβ-CGTase from Bacillus circulans strain 251 was cloned into the expression vector pET-20b（＋）. The vector was then transformed into Escherichia coli BL21（DE3）for extracellular production ofβ-CGTase. The activity in the supernatant of recombinant E. coli BL21（DE3）was 20 U/mL. Furthermore, the condition forβ-cyclodextrin（β-CD）preparation by this recombinantβ-CGTase was optimized. At 15%potato starch, pH5.5, 30℃, 2.5%-5%（V/V）cyclohexane, 10 Uβ-CGTase per gram substrate incubated for 24 hours, 75.3%of the starch was transformed intoβ-CD. This is the highest level ofβ-CD conversion by enzyme method at home and abroad.
出处
《生物技术通报》
CAS
CSCD
北大核心
2014年第8期175-181,共7页
Biotechnology Bulletin
基金
国家自然科学基金项目(31100048)
关键词
环糊精葡萄糖基转移酶
Β-环糊精
酶转化
重组表达
淀粉
Cyclodextrin glycosyltransferase
β-cyclodextrin
Enzymatic conversion
Recombinant expression
Starch
