摘要
将来源于解淀粉芽孢杆菌(Bacillus amyloliquefaciens)的果聚糖蔗糖酶(levansucrase)基因进行克隆,并将其在Escherichia coli BL21(DE3)中表达。对发酵产酶后的菌体进行破壁和离心,粗酶液经镍柱纯化后,进行酶学性质研究。结果表明,重组酶的水解酶活和转移酶活最适温度分别为45℃和40℃,最适pH分别为6.5和6.0。此外,果聚糖蔗糖酶的K_m和V_(max)分别为150.74mmol/L和21.23μmol/(mL·min)。最后,在pH 6.0、40℃条件下,果聚糖蔗糖酶催化反应12 h后,体系中果聚糖质量分数可达34.05%。
Levansucrase from Bacillus amyloliquefaciens was cloned and heterologously expressed in Escherichia coli BL21(DE3). After purification,the enzymatic characterization of levansucrase was determined and analyzed. The optimum temperature of hydrolytic activity was 45 ℃ and the maximal transfructosylation activity was measured at 40 ℃. The optimum pH for hydrolytic and transfructosylation activities were 6.5 and 6.0,respectively. The Km and Vmax values for levansucrase were calculated to be 150.74 mmol/L sucrose and 21.23 μmol/(mL·min),respectively. Levansucrase-catalyzed reaction was investigated at pH 6.0 and 40 ℃. The result indicated that the content of levan was up to 34.05% in total products after 12 h.
作者
徐君
张言周
黎循航
管政兵
蔡宇杰
廖祥儒
XU Jun;ZHANG Yanzhou;LI Xunhang;GUAN Zhengbing;CAI Yujie;LIAO Xiangru(Key Laboratory of Industrial Biotechnology,Ministry of Education,Jiangnan University,Wuxi 214122,China;College of Bioscience and Bioengineering,Jiangxi Agriculture University,Nanchang 330045,China)
出处
《食品与生物技术学报》
CAS
CSCD
北大核心
2019年第3期124-129,共6页
Journal of Food Science and Biotechnology
基金
江苏省产学研前瞻项目(BY2014023-28)
无锡市科技发展农业支撑项目(CLE01N1310)
关键词
果聚糖蔗糖酶
解淀粉芽孢杆菌
重组表达
性质
levansucrase
Bacillus amyloliquefaciens
recombinant expression
characterization
