Propionic Acid Bacteria Research Articles

Production of probiotic kvass beverages enriched with pine nut shell extract and propionic acid bacteria

The aim of this study was to develop a new functional product: a probiotic kvass beverage (PKB) based on curd whey with the addition of polyphenols from Pinus sibirica shell extract and propionic acid bacteria (PAB). The studies conducted have shown that replacing water with curd whey in the traditional technology for preparing kvass wort contributes to the active growth of yeast and the accumulation of alcohol. Therefore, it has been established that the separate cultivation of yeast and PAB is optimal. The optimal parameters for producing a product with the best consumer properties were determined: the dose of yeast starter, the amount of PAB concentrates, the quantity of pine shell extract, and the duration of the cultivation stages. Fermentation of whey-based fermented kvass wort with a concentrate of PAB and pine shell extract enriches it with propionic, acetic, and free amino acids (FAA) and B vitamins. Also, it improves the consumer properties of beverages and the quality and functional properties of the finished product. Tannins give the product a brown color and a pleasant tart taste. The high antioxidant activity of tannins contributes to preserving the quality of beverages during long-term storage. Pronounced antagonistic and antimutagenic activities of the resulting drink were established due to the combined action of yeast, PAB, and pine shell extract. Based on the research, a technology for producing a PKB was developed.

Selection of probiotic microorganisms in the composition of a new biological preparation for farm animals

The idea of a healthy diet is gaining popularity, which justifies consumer interest in environmentally friendly and biologically complete livestock products. In this regard, the development and use of probiotic preparations in feeding farm animals and identifying the effectiveness of their use is an urgent task of our time. An essential step in creating new biological products is the study and selection of strains for the composition of the starter since the probiotic effect of microorganisms is determined by the set of natural properties they possess. In this work, the biological and technologically valuable properties of 12 strains of lactobacilli and 15 strains of propionic acid bacteria from the Siberian collection of microorganisms of the laboratory of the microbiology of milk and dairy products of the SRICM FGBNU FANZA (Siberian Research Institute of Cheese Making of Federal State Budgetary Scientific Institution of Federal Altai Scientific Center for Agrobiotechnology) department were studied to include them in the composition of a new probiotic preparation for farm animals. During the research, it was found that all strains of lactic acid rods actively fermented carbohydrates found in plant substrates and maintained their numbers not lower than a therapeutically significant level during 60 days of storage, i.e., showed high technology. Propionic acid bacteria exhibited high biological properties, i.e., they could produce vitamin B12 in amounts from 0.48 to 0.64 μg/cm3 and maintained their viability during six months of storage. As a result of research on the best manifestation of technologically valuable properties, two strains of lactic acid bacilli (SKM673 and SKM-681) and three strains of propionic acid bacteria (111, 112, 149) were selected that were promising for inclusion in the composition of a new probiotic preparation for farm animals.

Determination of the Toxicity and Sensitizing effect of a Therapeutic Probiotic agent against Intestinal and Concomitant human infections

Studies were conducted on the toxicity and possible sensitizing effect of the lyophilizate of a therapeutic probiotic agent from the most active strains of lactic acid and propionic acid bacteria isolated from healthy people: L. plantarum 2v/A-6+L. brevis B-3/A-26+L. acidophilus 27w/60+P. shermanii 8. Based on the studies conducted to evaluate acute toxicity with an oral single administration of probiotic agent solutions (lyophilizate of lactic acid and propionic acid bacteria) at doses of 300, 2,000, 4,000, and 5,001mg/kg of weight, the toxicity class of the preparation under study has been defined as a non-toxic substance. In the study on laboratory mice of subchronic (subacute) toxicity of probiotic agent (lyophilizate of lactic acid and propionic acid bacteria)) in doses of 5.0×106, 10.0×106, and 15.0×106 CFU, it has been found that the preparation does not have a toxic effect on the body in case of 28-day use. Studies of the chronic toxicity of the probiotic agent (lyophilizate of lactic acid and propionic acid bacteria) in doses of 5.0×106, 10.0×106, and 15.0×106 CFU, in laboratory mice have shown that this preparation does not have a toxic effect on the body in case of prolonged 60-day use and does not cause structural changes in internal organs. It has been established that the therapeutic probiotic agent (lyophilizate of lactic acid and propionic acid bacteria) does not have a potential sensitizing (allergenic) effect on rat peritoneal mast cells.

Development of Technology for the production of finished forms of Medicinal probiotics

The study aimed to develop a technology for the production of a finished form of medicinal probiotic agents against human intestinal infections based on active strains of lactic acid and propionic acid bacteria with a wide range of biological activity and resistance to antibiotics. From the laboratory collection of lactic acid and propionic acid bacteria isolated from the intestines of healthy people, two associations of bacteria were compiled with antagonism against test cultures of Staphylococcus aureus, Salmonella gallinarum, Mycobacterium B5, Candida albicans, Pasteurella multocida, Bacillus subtilis, Escherichia coli 8739, Klebsiella pneumoniae ATCC 700603 and ATCC BAA 2524, Staphylococcus aureus 3316 and 9, Salmonella enteritidis 35382, and Pseudomonas aeruginosa 835, as well as the ability to produce hydrolytic enzymes amylase and proteinase, B vitamins, and essential amino acids. The resistance of the selected associations of lactic acid and propionic acid bacteria to the used antibiotics has been studied, which will allow for using them, if necessary, in the complex therapy of diseases. Technology for the production of probiotic medication from these associations has been developed. It was found that the most active preparation in terms of bacterial titer and antagonistic activity and the most stable one during storage for 6 months was the liquid preparation obtained by growing association No. 2 (L. plantarum 2v/A-6+L. brevis B-3/A-26+L. acidophilus 27w/60+P. shermanii 8) on nutrient medium No. 1 (De Man, Rogosa and Sharpe agar with CoCl2) using 7% sucrose and 1.5% gelatin as a protector. The liquid preparation from association No. 5 grown on medium No. 1 showed a more complete preservation of production-valuable signs during storage compared to the results of using nutrient medium No. 4, while the use of protector No. 1 was more optimal. To test the stability during the storage of dry preparation forms, an accelerated method was used by warming them up for 15 minutes at 60°C. It was found that after warming up, the best preservation of viable bacterial cells was observed in association No. 2 on nutrient media No. 1 and No. 4, in association No. 5 on medium No. 4 dried with protector No. 2 (7% sucrose and 1.5% gelatin + 7% skim milk powder), while the titer of bacteria was equal to 1.2×109, 3.5×108, and 2.0±0.2×108 colony-forming units/g, respectively. Antagonistic activity in these association variants was observed against all test cultures taken into the study with zones of suppression of their growth ranging from 10 to 24 mm.

Features of selection of microorganisms in the composition of a new probiotic drug for farm animals

Nowadays, the idea of healthy eating is gaining popularity, which makes consumers interested in environmentally friendly and biologically nutritious animal products. In this regard, the development of probiotic preparations for farm animals and determination of the effectiveness of their use become urgent tasks. Important stages in the creation of new biopreparations are the study and selection of the most suitable strains, as the probiotic effect of the microorganisms included in the inoculum is determined by a set of technologically valuable properties they possess. In the course of the study, technologically valuable properties of 12 strains of lactobacilli and 15 strains of propionic acid bacteria from the Siberian Collection of Microorganisms (Laboratory of Microbiology of Milk and Dairy Products, Siberian Research Institute of Cheesemaking, FSBSI “Federal Altai Scientific Center of Agrobiotechnologies”) were studied in order to include them in the composition of a new probiotic preparation for farm animals. It was found that all the considered strains of lactic acid bacilli actively digested carbohydrates included in the composition of plant substrates, as well as maintained their abundance not below the therapeutically significant level for 60 days. Propionic acid bacteria produced 0.48 ± 0.01 to 0.64 ± 0.06 μg/cm3 of vitamin B12 and remained viable in numbers of tens of millions of cells for 6 months. As a result, two strains of lactic acid bacilli (SCM 673, SCM 681) and three strains of propionic acid bacteria (111, 112, 149) were selected according to the best manifestation of technologically valuable properties as promising for inclusion in the composition of a new probiotic preparation for farm animals.

Development of enriched bakery products using biotransformation in starter cultures of protein-containing vegetable additives

Introduction: In the bakery industry, the key task is to produce quality products from diverse raw materials for healthy public nutrition. Technologies include the use of additives to enhance quality, biotransformation methods with starters, and the selection of enzymes and microorganisms. Biotransformation modifies the raw material, resulting in a product with superior taste qualities and nutritional value. The use of starters requires careful selection of microorganisms to optimize product quality.Materials and Methods: The objects of research in the work were bakery products obtained by biotransformation of the studied plant raw materials, which was carried out by pure cultures of probiotic microorganisms - mesophilic homo- and heterofermentative lactic acid and propionic acid bacteria: Lactobacillus casei, L.plantarum, L.acidophilus, L.fermenti, L.brevis, Propionibacterium freudenreichii subsp. Shermanii. The work uses generally accepted standard methods for determining organoleptic and physico-chemical quality indicators of semi-finished products and finished bakery products. The indicator of resistance to microbiological spoilage of the developed bakery product was determined.Results: Results: The use of defatted soy flour and sunflower protein as sources of plant protein has been justified. Based on comprehensive experimental studies, a rational method was identified for introducing defatted soy flour into the starter at 25% of the flour mass, which involves acid and enzymatic hydrolysis followed by biotransformation with a bacterial starter based on a composition of lactic acid microorganisms. Additionally, to increase the content of protein balanced in amino acid composition, as well as macro and microelements, vitamins, and antioxidants, a dosage of sunflower protein was selected at 10% of the flour mass in the product recipe.Conclusion: A technology for enriched bakery products has been developed, and the nutritional value has been calculated. A comprehensive assessment of the quality of the finished products based on organoleptic and physico-chemical indicators has been conducted, and the shelf life has been determined.

SELECTION OF CONDITIONS FOR OBTAINING ECOLOGICALLY PURE DRY PROBIOTIC AGAINST MIXED INTESTINAL INFECTION FOR FARM ANIMALS

As a result of the study, the best viability of monocultures and associations under freeze drying has been determined. The best two protective media during storage and their composition are the following: media No.1 includes (%) sodium acetate - 2.5; sodium citrate - 2.5; sucrose - 10.0; and protective media No.2 containштп (%) sucrose 8.0; gelatin - 1.5; skim milk - 5.0. Thus the titer of bacteria equaled to values of 6.0x1010 and 4.2x1010 CFU / g, respectively. When determining the stability of dried preparations during storage of probiotic bacteria and their association, the best protective medium is No. 2 (sucrose 8.0%; gelatin - 1.5%; skim milk - 5.0%). The antagonistic activity of monocultures (lactic acid bacteria Lactobacillus plantarum1, Streptococcus salivarius 20n, Lactobacillus fermentum 15, propionic acid bacteria Propionibacterium shermanii 34) and associations based on these monocultures is preserved practically at the initial level upon freeze drying. A probiotic based on lactic acid and propionic acid bacteria can be used as a therapeutic and prophylactic agent against dyspepsia for farm animals. At the same time, there is no need for the use of antibiotics and other antibacterial agents for the treatment of diseased animals.

Effects of Glucosinolate-Enriched Red Radish (Raphanus sativus) on In Vitro Models of Intestinal Microbiota and Metabolic Syndrome-Related Functionalities.

The gut microbiota profile is determined by diet composition, and therefore this interaction is crucial for promoting specific bacterial growth and enhancing the health status. Red radish (Raphanus sativusL.) contains several secondary plant metabolites that can exert a protective effect on human health. Recent studies have shown that radish leaves have a higher content of major nutrients, minerals, and fiber than roots, and they have garnered attention as a healthy food or supplement. Therefore, the consumption of the whole plant should be considered, as its nutritional value may be of greater interest. The aim of this work is to evaluate the effects of glucosinolate (GSL)-enriched radish with elicitors on the intestinal microbiota and metabolic syndrome-related functionalities by using an in vitro dynamic gastrointestinal system and several cellular models developed to study the GSL impact on different health indicators such as blood pressure, cholesterol metabolism, insulin resistance, adipogenesis, and reactive oxygen species (ROS). The treatment with red radish had an influence on short-chain fatty acids (SCFA) production, especially on acetic and propionic acid and many butyrate-producing bacteria, suggesting that consumption of the entire red radish plant (leaves and roots) could modify the human gut microbiota profile toward a healthier one. The evaluation of the metabolic syndrome-related functionalities showed a significant decrease in the gene expression of endothelin, interleukin IL-6, and cholesterol transporter-associated biomarkers (ABCA1 and ABCG5), suggesting an improvement of three risk factors associated with metabolic syndrome. The results support the idea that the use of elicitors on red radish crops and its further consumption (the entire plant) may contribute to improving the general health status and gut microbiota profile.

Selection of an active association of Probiotic bacteria and the Optimal composition of the Nutrient medium for Cultivation to increase the Therapeutic and Prophylactic effectiveness of a Medicinal probiotic preparation against Intestinal infections

The study aimed to create associations of probiotic bacteria with a wide range of biological activity, resistance to antibiotics, and selection of the nutrient medium composition to increase the effectiveness of probiotics against intestinal infections in humans. The authors found that the tested associations of probiotic bacteria exhibited sufficient antagonistic activity to all test cultures taken in the experiment. Associations No. 2 on media 1 and 4, No. 5 on media 1 and 8, and association No. 9 on media 1 and 8 showed the greatest activity for most test cultures. These associations have a bacterial titer of nx1010colony-forming units/ml, contain proteolytic, amylolytic, and pectolytic enzymes, as well as B vitamins, such as B3, B5, B6, B8, and B12. The authors studied the resistance of selected associations of lactic acid and propionic acid bacteria to the antibiotics used, which allows these associations to be used in complex therapy if necessary. Selected nutrient media and active associations of probiotic bacteria with a wide range of biological activity and antibiotic resistance can be used to create effective targeted medicinal probiotic agents.

Effect of probiotic preparation on goat milk quality

The effect of the experimental probiotic drug "Plantarum" on the physico-chemical and microbiological parameters of milk of crossbred dairy goats was studied. This preparation was developed in the laboratory of microbiology of milk and dairy products of the Siberian Research Institute of Cheese Making of the Federal Altai Scientific Center for Agrobiotechnology. The preparation includes pure cultures of probiotic strains of lacto- and propionic acid bacteria from the "Siberian collection of microorganisms". Scientific and economic experiment was conducted in 2018-2020 on the territory of the Pervomaisky district of the Altai Territory. The objects of the study were crossbred dairy goats. In order to evaluate the effect of the experimental probiotic drug "Plantarum" on the milk quality of the experimental animals, four groups (20 animals in each group) of pregnant goats were formed: one control and three experimental. The goats of the experimental groups were fed the probiotic drug "Plantarum" in addition to the basic diet at the doses of 0.4, 0.6, and 0.8 ml/kg of body weight/day. The results showed that the content of the mass fraction of fat and protein in the milk samples of all experimental groups were within the norm for this type of animals regulated by GOST 32940-2014. It should be noted that the use of different doses of probiotic increased the fat mass fraction in milk from 0.06 to 0.13% and the protein mass fraction by 0.12% relative to the control. Physicochemical parameters (dry skimmed milk residue, titratable acidity, somatic cells) of milk of the experimental goats were within normal limits; no significant differences between the groups were found. There was a tendency to reduce the bacterial contamination of milk in the experimental groups compared to the control when determining the number of mesophilic aerobic and facultatively anaerobic microorganisms.

Investigation of the biochemical activity of starter compositions enriched with propionic acid bacteria on various raw materials

Currently, there is a need to develop an assortment of low-lactose or lactose-free dairy products and plant-based products due to an increase in the number of consumers with lactase deficiency, allergic to cow's milk components, cholesterol problems, etc. For the development of plant and lactose-free bioproducts, it is possible to use various starter cultures enriched with probiotics. Various starter cultures were used in the work, propionic acid bacteria were used as a probiotic. The objects were lactose-free milk and vegetable bases: rice milk, oat milk and coconut milk; the control was selected milk. A comparative analysis of the fermentation process of various compositions of starter cultures enriched with propionic acid bacteria on various raw materials was carried out. The duration of fermentation of vegetable raw materials is 8-10 hours, the acid-forming activity of combined starter cultures is quite high. The number of viable cells of lactic acid and propionic acid bacteria in the obtained bioproducts has a high value and amounts to 107-108 K.O.E. /cm3. This confirms that the nutrient medium for the cultivation of selected starter compositions is favorable, the microflora of the starter composition develops harmoniously. Lactic acid microorganisms and propionic acid bacteria make it possible to obtain fermented biological products with a variety of taste characteristics inherent in a certain type of raw material. According to the results of the research, the developed starter compositions meet the requirements for starter cultures, have valuable technological properties that allow expanding the range of plant and lactose-free biological products.

Nutritional and protective environmental factors for microbial consortium cultivation

Currently, the use of highly active probiotic strains for obtaining consortia with high biochemical and technological potential is relevant and promising in the dairy industry. Such probiotic microorganisms include propionic acid bacteria and Acidophilus bacillus. The creation of a consortium based on Propionibacterium freudenreichii Sh 85 and L. acidophilus makes it possible to develop specialized food products and biologically active additives with high probiotic properties. An inoculate was obtained based on pure cultures of Propionibacterium freudenreichii Sh 85 and L. acidophilus in a ratio of 2:1, which has a high biochemical activity and can provide a high level of enzymatic processes when co-cultured on a dairy medium. The nutrient medium based on whey has been optimized for obtaining the biomass of a consortium of propionic acid bacteria and Acidophilus bacillus. The optimal temperature range for biomass growth is (30±2) °C. The article shows the results of the selection of the optimal amount of cobalt ions in the nutrient medium. For normal biomass growth, high yield of viable cells of Propionibacterium freudenreichii Sh 85 and L. acidophilus cultures and vitamin B12 biosynthesis, a dose of 0.0025 g/l cobalt chloride was selected. The resulting biomass is characterized by a high titer of viable cells of propionic acid bacteria and Acidophilus bacillus 1012 k.f.u./cm3. The accumulation of vitamin B12 is active in the biomass. Cellular biomass is applicable as a biologically active additive for direct consumption and in the dairy industry as a bacterial concentrate.

Development of innovative fermented products by exploiting the diversity of immunomodulatory properties and fermentative activity of lactic and propionic acid bacteria

Many consumers nowadays demand plant-based milk analogs for reasons related to lifestyle, health, diet and sustainability. This has led to the increasing development of new products, fermented or not. The objective of the present study was to develop a plant-based fermented product (based on soy milk analog or on hemp milk analog), as well as mixes, using lactic acid bacteria (LAB) and propionic acid bacteria (PAB) strains, as well as consortia thereof. We screened a collection of 104 strains, from nine LAB species and two PAB species, based on their ability to ferment plant or milk carbohydrates, to acidify goat milk, soy milk analog and hemp milk analog, as well as to hydrolyze proteins isolated from these three products. Strains were also screened for their immunomodulatory ability to induce secretion of two interleukins, i.e., IL-10 and IL-12, in human Peripheral Blood Mononuclear Cells. We selected five strains: Lactobacillus delbrueckii subsp. lactis Bioprox1585, Lactobacillus acidophilus Bioprox6307, Lactococcus lactis Bioprox7116, Streptococcus thermophilus CIRM-BIA251, and Acidipropionibacterium acidipropionici CIRM-BIA2003. We then assembled them in 26 different bacterial consortia. Goat milk and soy milk analog fermented by each of the five strains or by the 26 consortia were tested in vitro, for their ability to modulate inflammation in cultured Human Epithelial Intestinal Cells (HEIC) stimulated by pro-inflammatory Lipopolysaccharides (LPS) from Escherichia coli. Plant-based milk analogs, fermented by one consortium composed of L.delbrueckii subsp. lactis Bioprox1585, Lc.lactis Bioprox7116, and A.acidipropionici CIRM-BIA2003, reduced the secretion of the proinflammatory cytokine IL-8 in HIECs. Such innovative fermented vegetable products thus open perspectives as functional foods targeting gut inflammation.

JOINT CULTIVATION OF REPRESENTATIVES OF THE GENERA PROPIONIBACTERIUM, LACTOBACILLUS, BIFIDOBACTERIUM ON UNIFIED MEDIA

Probiotic microorganisms are living non-pathogenic, non-toxigenic microorganisms that enter the intestine with food and have a positive effect on the body, normalising the composition and biological activity of the microflora of the digestive tract. Lactic acid bacteria of the genera Lactobacillus and Bifidobacterium occupy a prominent place among the microorganisms that make up probiotics. The presence of these bacteria in the gastrointestinal tract provides an antagonistic environment that is directed against pathogenic microorganisms and creates conditions for the growth and development of beneficial bacteria. Bifidobacterium and Lactobacillus can enhance the absorption capacity of food components, lactose tolerance, stabilise liver function by normalising bowel function and reducing blood ammonia levels. Recently, the spectrum of microorganisms that exhibit antagonistic properties and have a favourable effect on the vital activity of the organism has been expanding. Much attention is paid to propionic acid bacteria, which are part of the microflora of various biotopes. Propionic acid bacteria synthesise vitamin B12, bifidogenic growth factors and bacteriocins, have high adhesive and immunomodulatory properties, and their metabolites have antimutagenic effects. In this study, we analysed the possibility of individual and joint cultivation of representatives of the genera Propionibacterium, Lactobacillus and Bifidobacterium on unified media containing corn and yeast extracts. It was found that these nutrient media are effective for monocultivation of propionic acid bacteria and lactobacilli. At the same time, not only an increase in the optical density of propionic acid bacteria (3-fold), but also an increase in acid formation (2-fold on average) was observed. The possibility of joint cultivation of lactic acid and propionic acid bacteria by creating associations of two types was proved. The number of colonies of the studied microorganisms on selective nutrient media after cocultivation in unified media of both types was determined, the highest survival rate was observed for Propionibacterium. The antagonistic effect of both individual cultures and established associations against certain gram-positive bacteria and microscopic fungi was recorded.

Determination of the functional properties of protein hydrolysates by the in silico method

Bioactive peptides are of increasing interest to scientists. The development of peptidomics and bioinformatics contributes to a deeper study of peptides obtained by enzymatic hydrolysis of raw materials. In this work, the in silico method was used to study the properties and biological value of peptides identified in protein hydrolysates obtained by microbial fermentation of the broiler chicken gizzards in whey with the addition of bifidobacteria and propionic acid bacteria. The activity of the peptides was determined using the BIOPEP database. Potential toxicity and such properties as hydrophobicity, hydropathicity, hydrophilicity, molecular weight of each peptide were predicted through the tool ToxinPred. The potential activity of the peptides was evaluated using the PeptideRanker database. The conducted studies made it possible to identify bioactive peptides TR, SY, VW, PPP, SW in hydrolysates, which have various physiological effects. Several peptides with high potential biological activity have also been identified. Due to the fact that not all peptides obtained during the fermentation of raw materials have been studied, in silico methods allow us to assess the feasibility of isolating certain peptides from hydrolysates.

Effect of a Probiotic Preparation Based on Lactic and Propionic Acid Bacteria on the Growth of Young Rainbow Trout Oncorhynchus Mykiss in Aquaculture

Effect of a Probiotic Preparation Based on Lactic and Propionic Acid Bacteria on the Growth of Young Rainbow Trout Oncorhynchus Mykiss in Aquaculture

Propiyonik Asit Bakterileri ile B12 Vitamini Üretimi ve Etkili Parametrelerin İncelenmesi

Propionic acid bacteria (PAB) are extremely important because of the metabolites they produce (vitamins, propionic acid, conjugated linoleic acid, and bioactive peptides). Nowadays, the increasing interest in healthy nutrition has led to the formation of the concepts of probiotics, postbiotics and functionality with studies. Vitamin B12 is one of the postbiotics produced by PAB and is known to be beneficial for human health. Due to its coenzyme feature, it plays a key role in the body process, as well as shows anti-inflammatory properties. The recommended dietary intake of vitamin B12 for adults is 4 μg/day. Although it is highly found in meat products, it is known that the bioavailability of B12 in dairy products is higher. Fermented dairy products, especially products that contain PAB in their natural microflora, are good tools for the production and intake of vitamin B12. In this study, the factors affecting the microbial production of vitamin B12 were examined.

Propionic Acid Fermentation—Study of Substrates, Strains, and Antimicrobial Properties

Since milk whey is an abundant dairy by-product and a significant threat to the environment, its utilization is of great interest. The study compares valorization of lactose and lactates—the main carbon sources of whey—by fermentation—an environmentally friendly process. Antimicrobials released during fermentation by food-grade bacteria can help increase the microbiological safety of food. Propionic acid—a strong antimicrobial—is obtained mainly by the petrochemical route, yet there is increasing interest in its synthesis in biotechnological pathway. Five strains of propionic acid bacteria (Acidipropionibacterium acidipropionici, Propionibacterium cyclohexanicum, Propionibacterium freudenreichii, Acidipropionibacterium jensenii and Acidipropionibacterium thoenii) were investigated for their ability to produce organic acids and biomass using Na lactate or lactose as carbon sources. Selected fermentates were investigated for their antimicrobial efficacy during in vitro studies with foodborne pathogens: Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Bacillus subtilis and Staphylococcus aureus. Results confirm that the production of acids and biomass is considerably influenced by the added carbon source. The tested fermentates have strong and specific antimicrobial activity against Pseudomonas aeruginosa, Bacillus subtilis and Staphylococcus aureus. In addition, inhibition of Staphylococcus aureus and Klebsiella pneumonia depends on the activity of produced bacteriocins. The article also discusses the possibility of increasing the antimicrobial activity of fermentates by acidification.

Effects of Initial Rice Bran Concentration and Inoculum's Ratio on Microbial Growth of Co-culture Fermentation

Co-culture fermentation is widely applied for its synergistic effects. The synergistic effects of lactic acid bacteria (LAB) and propionic acid bacteria (PAB) are reported to improve the ruminant feed efficiency through the supplementations of probiotics. However, although co-culture fermentation of LAB and PAB has been recently demonstrated, the effects of carbon source and inoculum’s ratio on the microbial growth in co-fermentation are still not well-explored. Thus, this study was carried out to investigate the effect of rice bran concentration, as carbon source and inoculum’s ratio on the growth of L. casei and P. jensenii in co-culture fermentation. Reducing sugar content was extracted from rice bran through autoclave at 121℃ for 15 minutes. Co-culture fermentation was carried out in 2 stages: rice bran extract concentration’s variation and inoculum’s ratio variation. Co-culture in 20% w/v of RBE concentration showed the highest yield coefficient of YX/S of 0.265 g biomass/g substrate and YP/S of 0.715 g propionic acid/g substrate. Therefore, 20% w/v RBE concentration was used for the study of inoculum’s ratio. The YX/S (0.254 g biomass/g substrate) and YP/S (0.653 g propionic acid/g substrate) of ratio 1:4 was slightly lower than ratio 1:8, but the viability of L. casei (8.934 log10 CFU/mL) and P. jensenii (9.420 log10 CFU/mL) was the highest in ratio 1:4. Although increase of PAB ratio can increase biomass produced, but ratio 1:4 can achieve higher microbes’ viability which is important in the development of probiotics products.

Probiotic microorganisms – Propionibacterium ssp

Propionic acid bacteria belong to probiotic microorganisms, probiotic properties of which have not yet been thoroughly investigated. The research describes the probiotic features of milk propionic acid bacteria, including growth at high acidity, tolerance to bile acid, ability to suppress pathogenic microorganisms, and antibiotic susceptibility, as well as the ability to extend the shelf life of various fermented milk products due to the synthesis of propionic acid. Propionic acid bacteria have a robust nature, which makes it easy to overcome technological difficulties in the process of optimizing production. This enables them to be used in the future for the production of various fermented probiotic foods.