Simple and rapid separation of diverse neoagaro-oligosaccharides

A rapid and simple method for obtaining pure and well-defined oligosaccharides was established by hydrolyzing agar with β-agarase from Vibrio natriegens . The conditions for enzymolysis were optimized as follows: temperature of 45 °C, pH of 8.5, substrate concentration of 0.3%, enzyme amount of 100 U/g and enzymolysis time of 20 h. Neoagaro-oligosaccharides with different degree of polymerizations were gained by hydrolyzing agar with β-agarase at different enzymolysis time. After removing pigment by activated carbon and salts by dialyzing, the enzyme hydrolysis solution was separated with Bio-Gel P2 column chromatography. Neoagaro-oligosaccharides with different degree of polymerizations were acquired. By comparing with standard substances, along with further confirmation by FTIR, MS and NMR, structures of the purified neoagaro-oligosaccharides were identified as neoagarobiose, neoagaroteraose, neoagarohexaose, neoagarooctaose, neoagarodecaose and neoagarododecaose with purities more than 97.0%, respectively. The present study established a method for rapid preparation of various monomers of neoagaro-oligosaccharides that may be of great significance for further study of bioactivities.