Abstract: Beta-1,3-glucan possesses extensive application and application values due to diverse biological activity. Curdlan, an extracellular bacterial polysaccharide, is a linear beta-1,3-glucan, and its water insolubility significantly limits its application. The aim of this study was to prepare the soluble curdlan oligomers (CRDO) for biological activities assay. In the homogeneous solution, CRDO structure change by acid hydrolysis and the influence of different factors on the degradation of curdlan measured by HPAEC-PAD was investigated. Compared with curdlan, the structure of CRDO was not changed measured by FTIR spectrometer and MALDI-TOF MS, and the degree of polymerization (DP) of CRDO obtained was 2 － 19 with the most abundance of DP 5. The reaction condition including the time and temperature of acid hydrolysis was optimized to 105 ℃ for 150－180 min. Therefore, the method described in this study is highly efficient for the rapid degradation of curdlan into CRDO.

Key words: curdlan, curdlan oligomers, fourier transform infrared spectroscopy (FT-IR spectroscopy), matrix assisted laser desorption/ionization- time of flight mass spectrometry (MALDI-TOF MS), high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD)