Properties of Geobacillus stearothermophilus levansucrase as potential biocatalyst for the synthesis of levan and fructooligosaccharides.
The production of levansucrase (LS) by thermophilic Geobacillus stearothermophilus was investigated. LS production was more effective in the presence of sucrose (1%, w/v) than fructose, glucose, glycerol or raffinose. The results (Top 57°C; stable for 6 h at 47°C) indicate the high stability of the transfructosylation activity of G. stearothermophilus LS as compared with LSs from other microbial sources. Contrary to temperature, the pH had a significant effect on the selectivity of G. stearothermophilus LS-catalyzed reaction, favoring the transfructosylation reaction in the pH range of 6.0-6.5. The kinetic parameter study revealed that the catalytic efficiency of transfructosylation activity was higher as compared with the hydrolytic one. In addition to levan, G. stearothermophilus LS synthesized fructooligosaccharides in the presence of sucrose as the sole substrate. The results also demonstrated the wide acceptor specificity of G. stearothermophilus LS with maltose being the best fructosyl acceptor. This study is the first on the catalytic properties and the acceptor specificity of LS from G. stearothermophilus.
Dept. of Food Science and Agricultural Chemistry, McGill University, 21,111 Lakeshore, Ste-Anne de Bellevue, Quebec H9X 3V9, Canada.
Lotthida
L
Inthanavong
Feng
F
Tian
Maryam
M
Khodadadi
Salwa
S
Karboune
D019149:Bioreactors; D002384:Catalysis; D005630:Fructans / Q000096:biosynthesis*; D005632:Fructose / Q000378:metabolism; D001411:Geobacillus stearothermophilus / Q000201:enzymology*; D006602:Hexosyltransferases / Q000096:biosynthesis*; D007700:Kinetics; D009844:Oligosaccharides / Q000096:biosynthesis*; D013379:Substrate Specificity; D013395:Sucrose / Q000378:metabolism; D013696:Temperature
D005630:Fructans; D009844:Oligosaccharides; C116580:fructooligosaccharide; D005632:Fructose; D013395:Sucrose; C072599:levan; D006602:Hexosyltransferases; C021513:levansucrase
Geobacillus stearothermophilus; acceptor specificity; fructooligosaccharides; kinetics; levan; levansucrase