Molecular weight determination
The molecular weight of the samples was determined by high-performance
liquid chromatography (HPLC) and gel permeation chromatography (GPC).
Dextran standards and 10 mg/mL of samples were dissolved in 0.7% sodium
sulfate solution, and analyzed by a LC-2030C3D series HPLC (Shimadzu,
Japan) system equipped with RID 20 and sepexsrtsec-100 column (7.8 × 300
mm, 5 μm) to determine the retention
time. The column was maintained at 35 °C with 0.7% sodium sulfate
solution as the mobile phase at a flow rate of 0.5 mL/min and an
injection volume of 10 μL. The
molecular weight of the sample was calculated by constructing a
calibration curve in which the molecular weight log of glucan standards
180, 1000, 5000, 12000, 50000 and 64650 Da was plotted using the Agilent
Chemical Station GPC Data Analysis software (Rev.A.02.01).