Production, characterization and In vitro antioxidant activities of exopolysaccharide from Weissella cibaria GA44

Exopolysaccharide (EPS) producing lactic acid bacteria (LAB) strain GA44 isolated from gari (a Nigerian traditional fermented cassava mash) was identified with 16S rRNA gene sequencing as Weissella cibaria. The EPS produced mainly composed of glucose and rhamnose sugar units and its molecular mass was about 2.8 × 105 Da. The fourier-transform infrared (FT-IR) spectrum analysis showed characteristics absorption peaks indicating the presence of –OH, C=O and C-H groups. Central composite design (CCD) and response surface methodology (RSM) were used to study the interactive effect of the significant factors on EPS yield. Under optimum conditions, the predicted maximum EPS produced 4.88 g/L while the actual experimental value was 4.80 g/L. The in-vitro antioxidant activities of the EPS showed good scavenging effects on superoxide anion radical and hydroxyl radical. The characteristics of this EPS isolated from food source will be useful in food industries and could also serve as a potential antioxidant.