Effects of yeast extract on the production and the quality of the exopolysaccharide, zooglan, produced by Zoogloea ramigera 115SLR

Although many studies have examined the influence of culture conditions on the production and composition of polysaccharides, little is known about th e factors influencing the quality of exopolysaccharides (EPS). In this work we studied the effect of yeast extract on the production, composition and molecular weight of the EPS zooglan produced by Zoogloea ramigera 115SLR. T his bacterium was grown on a new completely defined synthetic medium and on a medium containing yeast extract. Growth and polysaccharide production pe rformances were comparable on the two media with a glucose to exopolysaccha ride conversion yield of 35% (g/g). The polysaccharides produced on these t wo media have an identical composition but a different molecular weight and molecular weight distribution. The yeast extract medium leads to a more ho mogeneous polysaccharide solution.