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.

Lactic acid bacteria (LAB) bacteriocins can be considered as a bio-preservatives and an alternative to antibiotics, but the high manufacturing costs limit their commercial application. The screening of LAB strains for bacteriocinogenic activity was carried out and the effect of rye bran enzymatic hydrolysate (RBEH) on gene expression and bacteriocin production was evaluated. qPCR and RT-PCR was applied for bacteriocin gene detection and their expression quantification. The agar diffusion technique with the test strains of Bacillus spp., Staphylococcus spp. and Salmonella enterica was performed for antimicrobial activity assessment of LAB cultivated in MRS broth and RBEH (processed with proteases and cellulases). The genes of different bacteriocins were revealed for thirteen out of eighteen LAB strains, while the antimicrobial activity was detected only for four of them. The strains of Lactobacillus paracasei VKPM B-11657 and L. salivarius VKPM B-2214 with unnamed class IIb bacteriocin gene demonstrated the widest spectrum of activity. The growth patterns and bacteriocin gene expression differed between both strains and media. The activity of cell-free supernatants after cultivation in RBEH was slightly lower. However, the test strain of S. epidermidis was inhibited by L. paracasei cultivated in RBEH but not in MRS. Thus, rye bran can be applied as a sole source of nutrients for LAB fermentation and bacteriocin production.

Biodegradable polymers, specifically polylactide, are an important part of food packaging and medical devices. Microbiological synthesis uses cheap renewable raw materials and industrial waste to produce a high yield of lactic acid, the monomer of polylactide. This method needs new effective lactic acid producing strains, e.g., thermophilic bacteria. The research involved thermophilic bacterial strains isolated from soil and compost samples. Their ability to produce organic acids and extracellular enzymes was tested using the method of high-performance liquid chromatography (HPLC) and microbiological tests respectively. The real-time polymerase chain reaction method (PCR) detected L-lactate dehydrogenase structural genes of L-lactate dehydrogenase of Bacillaceae. Strain T7.1 was fermented using glucose and yeast extract as carbon and nitrogen sources, respectively. The optical purity of lactic acid was evaluated using quantitative gas chromatography on a chiral column to separate lactate isomers. The molecular genetic analysis of the 16S rRNA gene sequence was applied to identify strain T7.1. The chromatographic analysis proved that 10 out of 13 isolated thermophilic strains were effective lactic acid producers. They demonstrated proteolytic, amylolytic, or cellulase activities. During the fermentation, strain T7.1 produced 81 g/L of lactic acid with a peak productivity at 1.58 g/(L·h). The optical purity of the product exceeded 99.9% L-lactate. The genetic analysis identified strain T7.1 as Weizmannia coagulans (Bacillus coagulans). The research revealed a promising thermophilic producer of optically pure L-lactic acid. Further research is needed to optimize the cultivation conditions, design an effective and cheap nutrient medium, and develop engineering and technological solutions to increase the yield.

An interest to bacteriocins as natural alternative for antibiotics and chemical preservatives is grow at present. The selection of novel strains producing antimicrobial peptides is in focus. The probiotics are preferable because they are recognized as safe and thereby can be applied in medications, foods, feeds. Moreover, the benefits of probiotics for human and animal health is proved. The growth kinetics of industrial probiotic strains Lactobacillus plantarum B-11007, Lactobacillus salivarius B-2214 è Lactobacillus bulgaricus B-4626 in MRS broth was studied at present work. The pH value was not adjusted. The agar well diffusion assay was applied for antimicrobial activity of lactic acid bacteria evaluation. The growth inhibition areas of the test strains of Bacillus megaterium B-3750, Bacillus cereus ATCC 9634 è Staphylococcus aureus ÀÒÑÑ 43300 were measured and compared. The effect of organic acids produced was excluded. The strain of L. bulgaricus B-4626 produced the bacteriocins against Bacillus cereus ATCC 9634. The influence of pH-controlled conditions to the growth kinetics of L. plantarum B-11007 and bacteriocins production during fermentation in MRS broth was estimated. The samples were additionally concentrated in rotary film evaporator followed by the antimicrobial activity assay. The magnification of B. megaterium B-3750 inhibition was shown. As a result of the study, the sensitivity of the Bacillus megaterium B-3750 strain to the L. plantarum B-11007 bacteriocins was established.

Plant polyphenols are known for their numerous health-promoting properties. This article reviews the current state of research in two related fields, namely beneficial effects of flavonoids for human health, e.g., gut microbiome, and supercritical fluid extraction applied to flavonoids of plant origin. The review covered research articles registered in eLIBRARY.RU, PubMed, and Science Direct in 2005–2025. Polyphenolic compounds obtained from various berries were reported to have a positive impact on gut microbiota, e.g., they stimulated the growth of lactobacilli, bifidobacteria, and other beneficial microorganisms, as well as improved the adhesion of probiotic and pathogenic microbes to intestinal epithelial cells. The review revealed some promising application areas for berry extracts in the functional food industry. Polyphenols can be part of meat formulations due to their strong antioxidant activity. Their antimicrobial effect against a wide range of contaminants renders them good prospects in protecting food products from microbial spoilage. Supercritical extraction is a promising method that isolates biologically active substances from plant materials. The review summarizes its advantages and limitations, as well as the range of prospective co-solvents. Ultrasonication, pulse electric field, and enzymic pretreatment make supercritical extraction more efficient. In general, this extraction method proved to be an excellent means of isolating flavonoids and related compounds from various plants and their parts.