PRODUCTION AND CHARACTERIZATION OF THE POLYSACCHARIDE FROM PROPIONIBACTERIUM-ACIDI-PROPIONICI ON WHEY-BASED MEDIA

The effects of lactose, ammonium and phosphate on the production of extracellular polysaccharide from Propionibacterium acidi-propionici VM-25 were studied in whey-based media. The polysaccharide was composed of a water-soluble fraction (15% w/w), a water-insoluble fraction (27% w/w) and ca 65% (w/w) of ash. Up to 15 g/l of polysaccharide was produced during growth on partially deproteinated whey, supplemented with lactose, NH4Cl and KH2PO4, after incubation at pH 7.0 and 25-degrees-C for 90 h. The final viscosity of the medium remained under 20 centipoises at the end of the fermentation (100-140 h). The fermentation of whey enabled a reduction of the lactose content up to 50%. The polysaccharide-containing fractions were composed of glucose, galactose, mannose, rhamnose and fucose and had M(r) < 5800. The polysaccharide may have applications as a low viscosity stabilizing agent.