Sucrose-based biosynthetic process for chain-length-defined α-glucan and functional sweetener by Bifidobacterium amylosucrase.
A unique thermostable amylosucrase from Bifidobacterium thermophilum was produced as a recombinant protein with the half-life of 577 h at 50 °C. By adding 1.0 M fructose, turanose yield was improved from 22.7% to 43.3% with 1.0 M sucrose, and from 23.7% to 39.4% with 1.5 M sucrose. Sucrose consumption rate was greatest at 55 °C, but the lowest amount of turanose was produced. Thus, turanose yield from sucrose biomass was inversely proportional to reaction temperature and was highly dependent on [fructose]. Meanwhile, insoluble α-glucan yield was clearly reduced as [fructose] increased. With 1.0 M fructose + 1.0 M sucrose, glucan byproduct yield significantly decreased from 29.4% to 1.1%. Molecular weights of linear glucans were almost identical among various [sucrose]s and were homogenous with very low polydispersity. This unique dual reaction patterns of amylosucrase enzyme would be very useful for massive productions of two different biomaterials simply by changing sucrose biomass concentration.
['Choi|Seong-Won|SW|', 'Lee|Jung-A|JA|', 'Yoo|Sang-Ho|SH|']
D001426:Bacterial Proteins D001644:Bifidobacterium D004187:Disaccharides D005632:Fructose D005936:Glucans D005964:Glucosyltransferases D006863:Hydrogen-Ion Concentration D055550:Protein Stability D011994:Recombinant Proteins D013395:Sucrose D013549:Sweetening Agents D013696:Temperature
α-Glucan Amylosucrase Bifidobacterium thermophilum Turanose Sucrose Biocatalysis