Probiotics play a central role in the interaction of the producing microorganism with the environment including different hosts. According to the beneficial effects that these microbes obtain, 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 Klebsiela 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. Characterization materials enveloped their thermal characteristics (TGA/ DTA analysis) and structure using: scanning electron microscopy (SEM), FTIR, and particle size distribution. The high survival rate of L. reuteri B2 at low pH from 2.0 to 4.0 and in the presence of the bile salts, at concentrations up to 0.30%, was obtained. L. reuteri B2 showed strong antimicrobial activity and the best protection microencapsulated with Na-alg + SM in simulated gastric juices (SGJ). EPS extracted from L. reuteri B2, were analyzed and characterized using chemical and biological analysis of this polymer. Functional characteristics of the producing strain, such as, adhesion assay to colonocytes, antioxidative and cytotoxic properties of EPS were also determined.
Mina Popovic, PhD, is currently working as Assistant Research Professor at Institute of Chemistry, Technology, and Metallurgy, National Institute of the Republic of Serbia. She graduated on December 2009 at Department of Biochemical Engineering and Biotechnology, Faculty of Technology and Metallurgy, University of Belgrade, Serbia. She got a full fellowship for PhD studies in Italy. She defended her PhD thesis on February 2015. at PhD School of Science and Technologies for Health Products, Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy. During the PhD studies she got the fellowship as visiting research assistant in the laboratory of Professor Dr. David A Mills, Institute Robert Mondavi, Departments of Food Science and Technology at the University of California. She supervised and worked with students during their masters studies and thesis. She is interested in the field of prebiotics and probiotics, focusing on Lactic Acid Bacteria (LAB) and bifidobacteria, biopolymers and its modifications, carrires, microencapsulation, exopolysaccharides, beneficial effects of the prebiotics and probiotics on human health. Last publication: ”Characterization of potential probiotic strain, L. reuteri B2, and its microencapsulation using alginate-based biopolymers”, doi: 10.1016/ j.ijbiomac.2021.04.177.