A new thermostable β-glucosidase mined from Dictyoglomus thermophilum: properties and performance in octyl glucoside synthesis at high temperatures.
A new β-glucosidase (DtGH) representing 40% identity with an apple seed glycosidase (ASG) was cloned from Dictyoglomus thermophilum. DtGH showed extremely high thermostability in aqueous solution, with half-lives of 533, 44, and 5 h measured at 70, 80 and 90 °C, respectively. Therefore it was used for direct glycosylation of n-octanol at 70 °C instead of 50 °C as usually. As a result, the glucose based conversion was increased by 27%, but the time spent to reach equilibrium was decreased from 7 d to 3 d. This enzyme also exhibited excellent stability under the reaction environment, retaining 70-80% of its initial activity after 7 d of incubation at 70 °C in either 1.7 M glucose solution or octanol-aqueous (85:15, v/v) system. It could retain part of synthetic activity even in boiling water. Owing to the strong glucose-tolerance and extremely high thermostability, DtGH should be promising for various glucosides synthesis.
Laboratory of Biocatalysis and Synthetic Biotechnology, East China University of Science and Technology, Shanghai 200237, China.
Zheng-Zheng
ZZ
Zou
Hui-Lei
HL
Yu
Chun-Xiu
CX
Li
Xin-Wen
XW
Zhou
Chihiro
C
Hayashi
Jie
J
Sun
Bao-Hong
BH
Liu
Tadeyuki
T
Imanaka
Jian-He
JH
Xu
D001419:Bacteria / Q000201:enzymology*; D004795:Enzyme Stability; D005798:Genes, Bacterial / Q000235:genetics; D005960:Glucosides / Q000096:biosynthesis*; D006358:Hot Temperature; D006868:Hydrolysis; D007700:Kinetics; D001617:beta-Glucosidase / Q000302:isolation & purification* / Q000378:metabolism
D005960:Glucosides; C018619:octyl-beta-D-glucoside; D001617:beta-Glucosidase