Studies on the Fermentation Conditions and Anti-tumor Effect of Exopolysaccharide from Rhizobium sp. N613

Abstract:

The potential of Rhizobium sp. N613 to produce the exopolysaccharide (REPS) was studied in this paper. Using an orthogonal design in a flask-shaker culture system, the fermentation medium and conditions of synthesizing REPS were optimized. Based on these results, the fermentation kinetic parameters were obtained in the batch fermentation with a 10L fermentor. The REPS yield of 11.31g/L was achieved by metabolic regulation during 40 h fed-batch fermentation. Transplanted tumor models of sarcoma 180 in mice were used to evaluate the anti-tumor effect. The result of anti-tumor activities showed that inhibition rate was 53.40%, when dose of REPS was 5mg/kg. These results indicate that REPS has the following properties: the short duration of fermentation, the high yield, the low cost, the effective immunocompetence and thickening. Thus, REPS has the value of development and application.

Key words:Rhizobium sp., Exopolysaccharide, Optimization, Fermentation, Anti-tumor