Comparison of two processes for isolation of exopolysaccharide produced by Lactobacillus acidophilus

Exopolysaccharides (EPS) are currently employed as additives in a wide variety of food products, in which they serve as thickening, stabilizing, emulsifying or gelling agents. On the other hand, probiotic microorganisms that belong to a group of lactic acid bacteria-which nowadays are recognized to exhibit beneficial effects upon health, produce EPS. In this work, the strain Lactobacillus acidophilus LAC has been examined for its EPS production capacity; two process of EPS isolation were also assessed, via testing of two alternative routes for precipitation of medium proteins, using xanthan gum as control. The treatment with sulfosalicylic acid to remove proteins during EPS isolation revealed a decrease of mannoprotein co-precipitation, whereas treatment with trichloroacetic acid decreased the co-precipitation of lactose and produced less variability in EPS quantification.