Production of exopolysaccharides by Lactobacillus helveticus MB2-1 and its functional characteristics in vitro

The production, characterization and functional properties in vitro of exopolysaccharides (EPS) of Lactobacillus helveticus MB2-1 with whey solution as basal medium were investigated. For EPS production, the strain grew well at 37 °C and 3 g/L MgSO4 with soya peptone as optimum nitrogen source. The maximum yield of EPS (753 mg/L) was obtained with the presence of lactose and soya peptone at concentrations of 80 g/L and 20 g/L, respectively. The EPS was found to be heteropolymer composed of galactose, glucose and mannose in a molar ratio of 1.00:1.69:3.54 with molecular weight about 2.0 × 105 Da. The EPS showed as a strong emulsifier in different oils/hydrocarbon substrates. The EPS also showed potent antioxidant effects, such as the abilities to scavenge hydroxyl, superoxide and DPPH radicals, and chelating ability on ferrous ion in a dose-dependent manner. In addition, antibiofilm activities by inhibition of three biofilm forming foodborne pathogenic bacteria were evident. The investigation demonstrated that the EPS from L. helveticus MB2-1 had potentials as a multi-functional natural ingredient for therapeutic and health foods.