Optimization of fermentation conditions for soluble extracellular polysaccharide production by Alcaligenes Faecalis AF 01

For the production of exopolysaccharide( EPS) from Alcaligenes Faecalis AF01,single-factor test and orthogonal experimental design were employed to optimize the fermentation conditions.The results showed that the optimal medium components were consisted of 50 g / L sucrose,1.1 g / L KNO_3,0.5 g /L yeast extract and 15 g /L CaCO_3.The optimal fermentation conditions were incubation time of 4 d,the initial p H of 7.0,2.5% inoculum amount,shaking speed of 200 r / min and culture temperature of 30 ℃.Under the optimized conditions,the yield of the soluble extracellular polysaccharide was significantly improved and a maximum EPS yield of 10.8 g / L was achieved.The optimized medium and our results provided some important data for commercial production of this polysaccharide.