Characterization and biological activity of exopolysaccharide extracted from novel probiotic strain L. reuteri B2., as novel biomaterial

Abstract

Probiotics as the most promising group of microbes have the possibility to synthesize metabolites, that can be used in different industries over the world. In this study, we investigated the probiotic activity of the Lactobacillus reuteri B2, as well as, the exopolysaccharides (EPS) that this strain produced. L. reuteri B2 was isolated from the feces of C57BL/6 mice and assessed on probiotic activity. L. reuteri B2 was identified by 16S rDNA sequencing, in which the cell viability in acidic conditions at pH 2.0 was 64% after 2 h, and in the presents of 0.30% of the bile salts, after 6 h, was 37%. Antimicrobial assay with L. reuteri B2 showed maximum diameters against K. oxytoca J7 (12.5±0.71mm). We further hypothesized if L. reuteri B2 strain in the free form can survive all conditions in the gastrointestinal tract (GIT) then the utilization of the appropriate biomaterials would ameliorate its stability and viability in GIT. L. reuteri B2 was microencapsulated into sodium alginate- (Na-alg) and different content of Na-alg and sodium maleate (SM) beads. Second hypothesis was if a novel EPS, extracted and isolated from L. reuteri B2, that obtain biological activity can be used as biomaterial. Characterization of this EPS enveloped FTIR, NMR, SEM, XRD, TGA/DTG analysis, biological assays, antioxidative activity, cytotoxic assay (MTT), and adhesion assay of L. reuteri B2 to HT29 cells. This EPS obtained a high scavenging effect of 76% at 2mg/mL of EPS in ABTS assay, while in MTT assay showed that did not have a cytotoxic effect.