The health benefits of probiotics are beyond doubt. The positive effects of lactobacilli and bifidobacteria on the function of many body systems have been repeatedly proven by various studies. To completely realize the potential of probiotic microorganisms, the strains should be tested by the greatest combination of characteristics that contribute to the wellness of the host. In this work, for the first time, a combined assessment of the probiotic properties and vitamin B-producing potential of various species and strains of bifidobacteria and lactobacilli was carried out. The presence of an additional advantage, such as vitamin-producing ability, can prevent vitamin deficiency both at the level of the consumption of fermented foods, when the enrichment will occur naturally on the spot, and during colonization by these intestinal strains, when synthesis will occur in vivo. To select potential probiotics, the stress tolerance ability of 16 lactic acid bacteria and bifidobacteria strains to low pH values, bile, and proteolytic enzymes, as well as their ability to autoaggregate, were studied under conditions of modeling the gastrointestinal tract in vitro. The ability of the strains to extracellularly accumulate water-soluble B vitamins was evaluated by capillary electrophoresis. Among the tested strains of bifidobacteria, B. adolescentis VKPM AC-1662 is of interest; it was characterized by the greatest stress tolerance ability and the ability to autoaggregate, in addition to the extracellular synthesis of riboflavin and pyridoxine. Among lactic acid bacteria, L. sakei VKPM B-8936 demonstrated the greatest tolerance to low pH, L. plantarum VKPM B–11007 to duodenal conditions, L. acidophilus VKPM B-2213 to pepsin, and L. salivarius VKPM B–2214 to pancreatin. The highest percentage of autoaggregation was observed in L. salivarius VKPM B-2214, which also accumulated the largest amount of pantothenic acid, but it was sensitive to stress conditions. The obtained results could be used to create new products enriched with probiotics and B vitamins.

A number of mechanisms have been proposed explaining probiotics and prebiotics benefit human health, in particular, probiotics have a suppression effect on pathogen growth that can be enhanced with the introduction of prebiotics. In vitro models enhanced with computational biology can be useful for selecting a composition with prebiotics from new plant sources with the greatest synergism. Water extracts from burdock root and Jerusalem artichoke tubers were purified by ultrafiltration and activated charcoal and concentrated on a rotary evaporator. Fructans were precipitated with various concentrations of ethanol. Bifidobacterium bifidum 8 VKPM AC−2136 and Staphylococcus aureus ATCC 43300 strains were applied to estimate the synbiotic effect. The growth of bifidobacteria and staphylococci in monocultures and cocultures in broths with glucose, commercial prebiotics, as well as isolated fructans were studied. The minimum inhibitory concentrations (MICs) of lactic and acetic acids for the Staphylococcus strain were determined. A quantitative model joining the formation of organic acids by probiotics as antagonism factors and the MICs of pathogens (as the measure of their inhibition) was tested in cocultures and showed a high predictive value (R2 ≥ 0.86). The synbiotic factor obtained from the model was calculated based on the experimental data and obtained constants. Fructans precipitated with 20% ethanol and Bifidobacterium bifidum have the greater synergism against Staphylococcus.

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Synbiotic compositions have a great potential for curing microbial intestinal infections. Novel targeted synbiotics are a promising field of the modern functional food industry. The present research assessed the effect of various fructan fractions, initial probiotic counts, and test strains on the antagonistic properties of synbiotics. The research involved powdered roots of Arctium lappa L. and strains of Bifidobacterium bifidum, Bacillus cereus, and Salmonella enterica. The experiment was based on the central composite rotatable design. A water extract of A. lappa roots was purified and concentrated. Fructan fractions were precipitated at various concentrations of ethanol, dried, and sub jected to carbon-13 nuclear magnetic resonance (13C-NMR) spectrometry. The bifidobacteria and the test strains were co-cultivated in the same medium that contained one of the fractions. Co-cultivation lasted during 10 h under the same conditions. The acid concentrations were determined by high-performance liquid chromatography to define the synbiotic factor. The obtained fructans were closer to commercial oligofructose in terms of the number and location of NMR peaks. However, they were between oligofructose and inulin in terms of signal intensity. The response surface analysis for bacilli showed that the minimal synbiotic factor value corresponded to the initial probiotic count of 7.69 log(CFU/mL) and the fructan fraction precipitated by 20% ethanol. The metabolites produced by the bacilli also affected their growth. The synbiotic factor response surface for the experiments with Salmonella transformed from parabolic to saddle shape as the initial test strain count increased. The minimal synbiotic factor value corresponded to the lowest precipitant concentration and the highest probiotic count. The research established a quantitative relationship between the fractional composition of fructans and the antagonistic activity of the synbiotic composition with bifidobacteria. It also revealed how the ratio of probiotic and pathogen counts affects the antagonism. The proposed approach can be extrapolated on other prebiotics and microbial strains in vivo.

Introduction. Obtaining protein and vitamin fodder is one of the urgent tasks that modern industrial biotechnology has to solve. Another task is a search of novel medium compositions for microbial fermentation that can lower production costs. Russian food industry produces a significant amount of sunflower seed processing byproducts every year. Sunflower meal is a promising source of sunflower protein isolate. The research objective was to develop a new technology for the production of Bacillus megaterium bacterial biomass for fodder purposes. Study objects and methods. The research featured a sunflower protein isolate, an enzyme complex Protex 7L, and a B. megaterium strain (VKPM B-3750). The carbohydrate content was determined using a modified Bertrand method. Amine nitrogen was studied using formol titration, the number of viable cells – by the Koch method, the content of amino acids – by capillary electrophoresis. Results and discussion. When processed with enzyme complexes, sunflower protein can be an alternative source of nitrogen for industrial fermentation. The study featured amino acid of sunflower protein isolate and enzymatic hydrolyzate obtained using Protex 7L. A comparative analysis of the content of amino acids in the hydrolyzate and the protein isolate showed that enzymatic hydrolysis can significantly increase the content of free amino acids in the medium available for microbial accumulation. The research proved that sunflower protein enzymatic hydrolyzate obtained using Protex 7L can be used to cultivate strains of B vitamins producers. Conclusion. Sunflower protein enzymatic hydrolyzate can be used as a nitrogen source for B vitamins producer fermentation and as an alternative to expensive meat peptone. The research involved technical and economic assessment of the B. megaterium fermentation on enzymatic hydrolysates of sunflower protein at a production capacity of 100 kg per year. The cost of the protein-vitamin supplement was calculated as 413 rubles per kg, while the market price could reach 826 rubles per kg. The payback period for capital expenditures was estimated at 1.5 years. Thus, replacing commercial meat peptone with sunflower protein enzymatic hydrolyzate obtained with Protex 7L reduced the cost of 1 kg of feed additive by three times without affecting B. megaterium. Overproduction of B vitamins by the B. megaterium strain on a medium containing sunflower protein hydrolyzate requires optimization of fermentation conditions.