In Vitro Evaluation of Probiotic Potential of Selected Lactic Acid Bacteria Strains

Research of human microbiome demonstrates that in order to develop next generation of probiotic agents, it is necessary to choose bacterial strains featured by special properties, such as the ability of the cells to attach to intestinal walls, resistance to bile and acids, bacteriocin synthesis, antioxidative and antipathogenic activity, and survivability in intestines. Thirty-three strains of lactic acid bacteria of Lactobacillus and Lactococcus genera from the Lomonosov Moscow State University Collection of Microorganisms (CM MSU) have been tested for important probiotic properties which assist these bacteria to settle effectively in intestines: cell adhesion, ability to form biofilms, agglutination with lectin (concanavalin A), and antimicrobial activity. The results of experiments clearly demonstrate that all these properties can be classified as strain characteristics and differ even within the same species. Besides the cultures of Lactobacillus with good agglutination ability with concanavalin A (Lact. caucasicus CM MSU 155, Lact. brevis CM MSU 521), we also discovered strains with high adhesion properties (Lact. acidophilus CM MSU 146—89% affinity for hexadecane; Lact. paracasei CM MSU 527—85%; Lact. plantarum CM MSU 508—78%; Lact. caucasicus CM MSU 155—70%; and Lact. delbrueckii CM MSU 571—57%), biofilm formation ability with a hydrophobic carrier (Lact. plantarum CM MSU 588—OD590 of crystal violet extracts = 1.336; Lact. brevis CM MSU 521—OD590 = 1.207; and Lact. brevis CM MSU 535—OD590 = 1.151), and with high antimicrobial activity specially to Staphylococcus aureus. Lact. brevis CM MSU 521 possesses the best property combination, which makes it potentially applicable as a very good lactic acid probiotic strain.