Screening For Potential Exopolysaccharide Producers From Lactobacillus spp Isolated From Locally Fermented Milk (Nono)

Abstract

Exopolysaccharides (EPS) are exogenous bacterial sugar polymers with many applications in dairy, pharmaceutical and cosmetic industries, using it as thickeners, stabilizers and gelling agents. The study aimed to screen for potential exopolysaccharide producers from Lactobacillus spp. isolated from locally fermented milk (nono). Twenty-five nono Samples were collected from Wambai market, Kano. Lactic acid bacteria were isolated using de Man Ragosa and Sharpe Agar. Isolates were identified by API 50 CHL kit and web, and screened for EPS production in which the EPS was extracted and quantified using the phenol-sulphuric method. Next, the influence of carbon source (Glucose, Sucrose and Lactose) and concentrations on EPS were evaluated on some of the isolated strains. The functional groups of the EPS were confirmed using FTIR. The isolated Lactobacillus spp. were all Gram positive, catalase and oxidase negative, API identification yielded; Lactobacillus acidophilus 1, Lb. brevis 1, Lb. fermentum, Lb. paracasei ssp paracasei, Lb. acidophilus 3. Ten isolates yielded EPS in the range of 248.33mg/l - 07.83mg/l. The FTIR analysis of extracted EPS produced peaks around 3,300–881cm-1. Hence the study has brought to light the presence of potential EPS producing LAB in nono, which could be further exploited to harness their potential.