Fermentation optimization, characterization and bioactivity of exopolysaccharides from Funalia trogii

Optimization of culture conditions for exopolysaccharide (EPS) by Funalia trogii in submerged culture was investigated using one-factor-at-a-time method and uniform design (UD). Under the optimized conditions, the maximum concentration of EPS was 8.68 g/l. After EPS was deproteinized by Sevag method, two groups of EPSs (designated as Fr-I and Fr-II) were obtained from the culture filtrates by gel filtration chromatography on Sepharose CL-6B. Furthermore, EPSs were characterized by size exclusion chromatography (SEC) coupled with a multiangle laser-light scattering (MALLS) and refractive index (RI) detector system. The weight-average molar masses of the Fr-I and Fr-II were determined to be 1.007 × 105 and 2.393 × 104 g/mol, respectively. The root mean square (RMS) radii for both peaks ranged from 9.7 to 10.8 nm with no clear trends. Pharmacology experiments indicated F. trogii EPS were useful to the therapy of free radical injury and cancer diseases.