The effects of cell-free extracts derived from probiotic strains Bifidobacterium bifidum and Lactobacillus reuteri on the proliferation and biofilm formation by Lactobacillus reuteri in vitro

Abstract

The aim of the research was to investigate the ability of cell-free extracts, containing derivatives of probiotic strains Bifidobacterium bifidum and Lactobacillus reuteri , to influence the proliferation and biofilm formation by Lactobacillus reuteri in vitro ; to evaluate the prospects for the creation of new metabiotics and means of increasing the overall productivity of probiotic cell biomass based on them. Materials and methods . Cell-free extracts were obtained from probiotic strains B. bifidum 1 and L. reuteri DSM 17938 by the authors’ method. Probiotic strain L. reuteri DSM 17938 used as a test culture. The investigation of the proliferation and biofilm formation by L. reuteri was carried out by spectrophotometric method using a microtiter-plate reader “Lisa Scan EM” (Erba Lachema s.r.o., Czech Republic). Results . It has been established that the cell-free extract obtained from L. reuteri culture grown in its own disintegrate, supplemented with glycerol and glucose, is the only one of all studied, which stimulates both proliferation and biofilm formation by L. reuteri . The cell-free extracts, obtained from L. reuteri and B. bifidum disintegrates and from L. reuteri culture, grown in its own disintegrate, stimulate proliferation of test-culture to varying degrees (depending on the type of extract and its content in the culture medium), but have a significant inhibitory effect on the biofilm formation by L. reuteri . The extract, obtained from B. bifidum culture, grown in its own disintegrate, does not have a significant effect on proliferation and greatly suppresses the biofilm formation by L. reuteri . Conclusions . The results of the study allow us to positively evaluate the prospects for the creation of new metabiotics based on probiotic derivatives. Cell-free extract, obtained from L. reuteri culture, grown in its own disintegrate supplemented with glycerol and glucose can contribute to the survival and facilitate inoculation of the introduced probiotic in the gastrointestinal tract when used together. Derivative-containing extracts with a pronounced growth-stimulating effect can be the basis for creating the means of increasing the overall productivity of the probiotic cell biomass. The use of such means will increase the economic efficiency of probiotic cultures production. Obtained data induce further study of the biochemical composition, elucidation of the mechanism of cell-free extracts action and confirmation of their efficacy in vivo .