Screening and identification of a fungal β-glucosidase and the enzymatic synthesis of gentiooligosaccharide.
After screening with 0.1% esculoside and 0.03% FeCl(3), we identified from rotten wood a fungal isolate HML0366 that produces high amount of β-glucosidase. Phenotypic and rDNA internal transcribed spacer sequence analyses indicated that the isolate belongs to Aspergillus oryzae. The β-glucosidase produced by HML0366 had an activity of 128 U/g. high performance liquid chromatography analysis also demonstrated a high transglycosylation activity of the crude enzyme. The β-glucosidase was stable between pH 4-10 at 60 °C. A gentiobiose yield of 30.86 g/L was achieved within 72 h of the enzymatic reaction at pH 5 and 55 °C using 50% glucose as the substrate. For the first time, we report here the isolation of an A. oryzae strain producing β-glucosidase with high hydrolytic activities. The crude enzyme has a high transglycosylation activity, which enables the enzymatic synthesis of gentiooligosaccharides.
Qin
Yongling
Y
College of Life Science and Technology, Guangxi University, Nanning, Guangxi 531005, China.
Zhang
Yunkai
Y
He
Haiyan
H
Zhu
Jing
J
Chen
Guiguang
G
Li
Wei
W
Liang
Zhiqun
Z
D001236:Aspergillus oryzae / Q000145:classification / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D004795:Enzyme Stability; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D007700:Kinetics; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000096:biosynthesis*; D010802:Phylogeny; D013379:Substrate Specificity; D014934:Wood / Q000382:microbiology; D001617:beta-Glucosidase / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*
D005656:Fungal Proteins; D009844:Oligosaccharides; D001617:beta-Glucosidase