In Vitro Characterization of Lactic Acid Bacteria from Indonesian Kefir Grains as Probiotics with Cholesterol-Lowering Effect

Potensi Probiotik Bakteri Asam Laktat Asal Madu dari Tiga Jenis Lebah yang Berbeda

Certain strains of Lactic acid bacteria (LAB) especially from the genus of Lactobacillus and Bifidobacteria have been recognized to have health beneficial effect as probiotics. Honey has been known to have health beneficial effects and contains lactic acid bacteria. However, information pertaining the characteristics of LAB from honey is still limited. The present research aimed to isolate LAB from different types of honey and to evaluate their potency as probiotic. The LAB were enumerated and isolated from honey produced by three different honeybees: Apis cerana, Heterotrigona itama, and Trigona laeviceps. The results showed the count of LAB in three different honey ranged from 5.0x101 to 2.3x107 CFU/mL and affected by different time of sampling. The highest of average LAB count was found in honey of Heterotrigona itama. There were 48 Gram positive catalase-negative bacterial isolates obtained from the three different honey types. Twelve isolates were selected based on their survival in bile salt. The twelve selected isolates were capable of growing in MRSB pH 2.5, and MRSB containing 0.3% bile salt. They also exhibited strong antibacterial activity against pathogenic bacteria. Identification based on 16S rRNA revealed that of the twelve isolates, nine were identified as Lactiplantibacillus plantarum and three others as Pediococcus acidilactici. The twelve isolates showed high survival at low pH dan bile salt and exhibited antimicrobial activity against pathogen, hence they are considered as probiotic candidates.

Microbial Diversity of Six Commercially Available Kefir Grains

Natural kefir grains are rich in beneficial bacteria, and analysis of their microbial diversity is a necessary condition for developing and applying kefir grains. In this study, six commercially available natural kefir grains were used as raw materials to explore their microbial diversity by metagenomics. The results showed that there were 14794 genes in 6 kinds of natural kefir grains, and the number of unique genes of X1, X2, X3, X4, X5, X6 were 111, 11, 0, 1899, 552, 1, respectively. From the relative abundance table of boundary, phylum, class, order, family, genus and species, the microbial diversity at each level was analyzed.The two dominant genera at the genus level are Lactobacillus and Lactococcus, and the dominant species at the species level are Lactococcus lactis and Lactococcus kefiranofaciens, Lactococcus crispatus, and Lactococcus helveticus, etc. Species distribution and species diversity of each sample were analyzed by species heat map, principal component analysis and non-metric multidimensional calibration methods. The results showed that the microbial diversity of natural kefir grains from 6 different sources were different. The research can provide reference for the development and application of natural kefir grains in the field of dairy products.

Lactic acid bacteria isolated from Chinese traditional fermented milk as novel probiotic strains and their potential therapeutic applications

Lactic acid bacteria (LAB) are believed to have health-promoting properties to the host and can be used in therapeutics interventions; intriguingly, they have the property to produce bio-preservatives substances. Therefore, this study aimed to mine probiotics and evaluate their safety, functional properties, and cholesterol-lowering capability. Seven potential probiotic strains were compared from 56 LAB strains isolated from traditional Chinese fermented milk. The results showed that all tested strains are tolerant to gastric acidity (45.5-83.26) and bile salts (11.92-92.91%) and have antibacterial activity against Staphylococcus aureus ATCC25923 and Escherichia coli ATCC25922. Likewise, it lowered the cholesterol levels in vitro by live cells (26.57-45.76%) and dead cells (29.53-50.97%) with remarkable aggregation ability (13.8-43.71%). Antioxidant properties and produce short chain fatty acids (SCFAs) were strain-dependent features. Upon assessment of the safety, Enterococcus faecium NWAFU-BIO-AS14 exhibited virulence factors genes (VFs) of (mur-2ed, odc, and tet(K)) and + hemolysis activity. While Enterococcus faecium NWAFU-BIO-A-B24 and Limosilactobacillus fermentum NWAFU-BIO-B-S6 have VFs of (odc, vanC2, and ant(6)-Ia). Limosilactobacillus fermentum NWAFU-BIO-D-B2 has only (odc). Thus, they are not considered as safe probiotics. In contrast, Lactiplantibacillus plantarum NWAFU-BIO-BS29, Companilactobacillus crustorum NWAFU-BIO-AS16, and Lactobacillus gallinarum NWAFU-BIO-D-S7 are the safest and best strains, respectively, due to the absence of 16 VFs and their sensitivity to antibiotics such as kanamycin, erythromycin, tetracycline, gentamycin, vancomycin, streptomycin, chloramphenicol, and ampicillin. Accordingly, these strains have a high potentiality to be used as starter cultures or safely applied as perfect probiotics in functionals food and feed.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-022-03403-z.

Probiotic of Lactiplantibacillus plantarum NWAFU-BIO-BS29 Isolated from Chinese Traditional Fermented Milk and Its Potential Therapeutic Applications Based on Gut Microbiota Regulation

Lactic acid bacteria are one of the bioresources that can promote the host's health and have potential therapeutic applications. This study aimed to evaluate the probiotic properties of novel Lactiplantibacillus plantarum NWAFU-BISO-BS29 isolated in vitro from traditional Chinese fermented milk, assess its safety, and study its interaction with the gut microbiota using a BALB/c mouse model. The findings reveal that this strain had a high tolerance to gastric acidity (64.4%) and bile salts (19.83-87.92%) with remarkable auto-aggregation and co-aggregation abilities (33.01-83.96%), respectively. Furthermore, it lowered the cholesterol levels in dead cells (44.02%) and live cells (34.95%) and produced short-chain fatty acids (SCFAs). Likewise, it showed good antioxidant properties and strong antipathogen activity against Escherichia coli and Staphylococcus aureus with inhibition zones at 21 and 25 mm, respectively. The safety assessment results indicate that all of the virulence factor genes were not detected in the whole DNA; additionally, no hemolysis or resistance to antibiotics commonly used in food and feed was observed. Interestingly, the 16S rRNA gene sequencing of the mouse gut microbiota showed a marked alteration in the microbial composition of the administrated group, with a noticeable increase in Firmicutes, Patescibacteria, Campylobacterota, Deferribacterota, Proteobacteria, and Cyanobacteria at the phylum level. The modulation of gut microbial diversity significantly improved the production of SCFCs due to the abundance of lactobacillus genera, which was consistent with the functional gene predictive analysis and is believed to have health-promoting properties. Based on these results, our novel strain is considered a safe and good probiotic and could hold high potential to be used as a starter culture or to safely supplement functional foods as a probiotic and may provide new insights into therapeutic interventions.

Designer meat production, carcass quality, and hemato-biochemical parameters of broilers fed dietary synbiotic derived from trimmed asparagus by-products combined with probiotic supplementation

OBJECTIVE

This experiment investigated the effects of synbiotic supplementation produced from probiotics and prebiotics from trimmed asparagus by-products (TABP) on broiler chicken diets in order to yield designer meat production.

MATERIALS AND METHODS

A total of 320 one-day-old Ross 308® chicks were randomly allocated to dietary treatments with four replications each (n = 20). The dietary treatments were composed of a control group without supplementation and treatment groups fed with 10, 30, and 50 gm/kg of TABP supplementation in diets combined with 2 gm/kg probiotics.

RESULTS

The results showed that broilers fed dietary supplementation of TABP with 2 gm/kg had a lower level of total cholesterol and low-density lipoprotein cholesterol in the serum, which reduced the atherogenic indices of the serum, such as cardiac risk ratio and atherogenic coefficient (p < 0.05). In addition, the cholesterol content and the fatty acid profile of breast meat, including palmitic acid, oleic acid, saturated fatty acid, and omega 9 levels, also declined with the increasing levels of TABP inclusion (p < 0.05). Moreover, the supplementation of TABP in diets caused a decline in the atherogenic and thrombogenicity indices and a rise in Δ-9 desaturase (16) index and hypocholesterolemic to the hypercholesterolemic ratio of meat (p < 0.05).

CONCLUSION

Synbiotic supplementation of up to 30 gm/kg TABP combined with 2 gm/kg probiotics in the chicken diet can potentially be utilized for the production of designer meat.

Kefir microbiota and metabolites stimulate intestinal mucosal immunity and its early development

Kefir consists of a large number of probiotics, which can regulate or shape the balance of intestinal microbiota, and enhance the host's immune response. Kefir microbiota can shape the mucosal immunity of the body through SCFAs, EPS, polypeptides, lactic acid, and other metabolites and microbial antigens themselves, and this shaping may have time windows and specific pathways. Kefir can regulate antibody SIgA and IL-10 levels to maintain intestinal homeostasis, and its secreted SIgA can shape the stable microbiota system by wrapping and binding different classes of microorganisms. The incidence of intestinal inflammation is closely linked to the development and maturation of intestinal mucosal immunity. Based on summarizing the existing research results on Kefir, its metabolites, and immune system development, this paper proposes to use Kefir, traditional fermented food with natural immune-enhancing components and stable functional microbiota, as an intervention method. Early intervention in the immune system may seize the critical window period of mucosal immunity and stimulate the development and maturation of intestinal mucosal immunity in time.

Research Update on the Impact of Lactic Acid Bacteria on the Substance Metabolism, Flavor, and Quality Characteristics of Fermented Meat Products

This paper reviews the effects of domestic and foreign influences on the substance metabolism pathways and the flavor and flora of LAB in fermented meat products to provide a new theoretical basis for developing new products for the industrial application of lactic acid bacteria (LAB) in fermented meat products. LAB are extensively used among commonly fermented ingredients, such as fermented meat products and yogurt. As fermenting agents, LAB metabolize proteins, lipids, and glycogen in meat products through their enzyme system, which affects the tricarboxylic acid cycle, fatty acid metabolism, amino acid decomposition, and other metabolic processes, and decompose biological macromolecules into small molecules, adding a special flavor with a certain functionality to the final product. Metabolites of LAB in the fermentation process also exert nitrite degradation, as well as antibacterial and antioxidant functions, which improve the physical and chemical qualities of fermented meat products. While fermenting meat products, LAB not only add unique flavor substances to the products, but also improve the safety profile of fermented foods.

Levilactobacillus brevis from carnivores can ameliorate hypercholesterolemia: in vitro and in vivo mechanistic evidence

AIMS

To explore the probiotic and hypocholesterolemic potential of two Levilactobacillus brevis strains of carnivore origin along with selected underlying mechanisms.

METHODS AND RESULTS

L. brevis MT950194 and L. brevis MW365351 were analyzed in vitro for oro-gastro-intestinal stress tolerance, cholesterol reduction, cholesterol adsorption (through scanning electron microscopy) and bile salt hydrolase (BSH) activity. Strains could survive (> 80%) in oro-gastro-intestinal conditions, reduce high amount of cholesterol (35% and 54%) from media containing bile salts (0.3%) as compared with Lactobacillus acidophilus ATCC4356 and presented least pathogenicity towards mammalian cells. Exopolysaccharide production, cell surface cholesterol adherence and BSH activity were witnessed as possible cholesterol lowering mechanisms. In in vivo experiment, the treatments of hypercholesterolemic rats with L. brevis MT950194, L. brevis MW365351 and their mixture led to significant (p < 0.05) reduction in serum and hepatic cholesterol, low density lipids, cholesterol ratio, liver steatosis, and size of adipocytes. It further ameliorated diet induced changes in hepatic enzymes.

CONCLUSIONS

L. brevis MT950194 and L. brevis MW365351 from carnivores have probiotic pharmacological potential and can reduce serum cholesterol through surface adherence and BSH production.

SIGNIFICANCE AND IMPACT OF STUDY

These strains may be utilized in treating hypercholesterolemia and production of low fat functional foods.

Potentiality of Food-Isolated Lentilactobacillus kefiri Strains as Probiotics: State-of-Art and Perspectives

Lentilactobacillus kefiri is one of the main lactic acid bacteria species in kefir and it was also isolated from other fermented foods. Numerous strains have been isolated and characterized regarding its potential as probiotics for the development of novel functional foods. To our knowledge this is the first review focused on highlighting safety aspects and health beneficial effects reported for L. kefiri strains. Several L. kefiri strains lack of transmissible antibiotic resistance genes, are tolerant to the harsh conditions of the gastrointestinal environment, and could resist different preservation procedures. Moreover, many of the isolated strains have shown antimicrobial activity against pathogens and their toxins, exhibited immunomodulatory activity as well as induced some beneficial effects at metabolic level. Regarding all the scientific evidence, certain L. kefiri strains emerge as excellent candidates to be applied to the development of both food supplements and new fermented foods with health-promoting properties. However, the availability of genomic information is still very limited, so much more work must be done in order to explore the potentiality of L. kefiri as a probiotic and a source of bioactive metabolites.

Dairy Lactic Acid Bacteria and Their Potential Function in Dietetics: The Food-Gut-Health Axis

Fermented dairy products are the good source of different species of live lactic acid bacteria (LAB), which are beneficial microbes well characterized for their health-promoting potential. Traditionally, dietary intake of fermented dairy foods has been related to different health-promoting benefits including antimicrobial activity and modulation of the immune system, among others. In recent years, emerging evidence suggests a contribution of dairy LAB in the prophylaxis and therapy of non-communicable diseases. Live bacterial cells or their metabolites can directly impact physiological responses and/or act as signalling molecules mediating more complex communications. This review provides up-to-date knowledge on the interactions between LAB isolated from dairy products (dairy LAB) and human health by discussing the concept of the food–gut-health axis. In particular, some bioactivities and probiotic potentials of dairy LAB have been provided on their involvement in the gut–brain axis and non-communicable diseases mainly focusing on their potential in the treatment of obesity, cardiovascular diseases, diabetes mellitus, inflammatory bowel diseases, and cancer.

Folate in Milk Fermented by Lactic Acid Bacteria from Different Food Sources

Folates are essential micronutrients, and folate deficiency still occurs in many countries. Lactic acid bacteria (LAB) are known to be able to synthesize folates during fermentation, but the folate production is strain-dependent and influenced by the fermentation medium, presence of a folate precursor, and fermentation time. This study aimed to screen extracellular folate-producing LAB from local food sources and evaluate the factors influencing their folate biosynthesis during milk fermentation. The selection of folate-producing LAB was based on their ability to grow in folate-free medium (FACM), with folate concentrations quantified by microbiological assay. Growth of the 18 LAB in FACM varied between isolates, with only 8 isolates growing well and able to synthesize extracellular folate at relatively high concentrations (up to 24.27 ng/mL). The isolates with highest extracellular folate levels, Lactobacillus fermentum JK13 from kefir granules, Lactobacillus plantarum 4C261 from salted mustard, and Lactobacillus rhamnosus R23 from breast milk, were applied to milk fermentation. The last two isolates were probiotic candidates. The three isolates consumed folate when it was present in the milk, and its consumption was in line with their growth. The availability of folate precursors affected the amount of folate consumed, but did not lead to increased folate concentrations in the medium after 72 h fermentation. The results of this study indicate that these isolates cannot be utilized for producing folate in folate-containing milk, as it shows feedback inhibition on folate biosynthesis.

Kefir and Its Biological Activities

Kefir is a fermented beverage with renowned probiotics that coexist in symbiotic association with other microorganisms in kefir grains. This beverage consumption is associated with a wide array of nutraceutical benefits, including anti-inflammatory, anti-oxidative, anti-cancer, anti-microbial, anti-diabetic, anti-hypertensive, and anti-hypercholesterolemic effects. Moreover, kefir can be adapted into different substrates which allow the production of new functional beverages to provide product diversification. Being safe and inexpensive, there is an immense global interest in kefir’s nutritional potential. Due to their promising benefits, kefir and kefir-like products have a great prospect for commercialization. This manuscript reviews the therapeutic aspects of kefir to date, and potential applications of kefir products in the health and food industries, along with the limitations. The literature reviewed here demonstrates that there is a growing demand for kefir as a functional food owing to a number of health-promoting properties.

Selection of potential probiotics with cholesterol-lowering properties for probiotic yoghurt production

From 61 lactic acid bacteria (LAB) isolates, three had good cholesterol-lowering properties, with Limosilactobacillus fermentum KUB-D18 having the highest cholesterol assimilation (68.75%) (51 µg/10⁹ CFU). In addition, Lactiplantibacillus pentosus HM04-25 and L. pentosus HM04-3 had the two highest levels of bile salt hydrolase (BSH) activity (22.60 and 21.45 U/mL, respectively). These three strains could resist four antibiotics (aztreonam, vancomycin, teicoplanin, and nalidixic). However, fortunately, they contained no mobile antibiotic resistance genes. To evaluate the influence of probiotic strains in yoghurt production, L. fermentum KUB-D18, L. pentosus HM04-25, or L. pentosus HM04-3 were simultaneously cultured with commercial yoghurt starter (YF-L812) and incubated at 43 °C for 6 h. During yoghurt fermentation, the total bacteria in the yoghurt tended to increase from 7.39 to 8.90 log CFU/mL. The growth rates of two probiotic strains (L. pentosus HM04-25 and L. pentosus HM04-3) were stable at 6.06 to 6.62 log CFU/mL. Only the rate for L. fermentum KUB-D18 increased (to 7.5 log CFU/mL). These three probiotics did not affect the physical characteristics of yoghurt. The total soluble solids, pH, and titratable acidity values of the probiotic yoghurts were similar to the control yoghurt at 30°Brix, 4.91, and 0.90%, respectively. The firmness values of the probiotic yoghurts and the control were not significantly different (p > 0.05). Differentiation of the appearance of color, odor, flavor, and texture between the control yoghurt and the probiotic yoghurts was investigated using 56 volunteers and no significant differences were identified. Additionally, sensory evolution revealed that the acceptability of the probiotic yoghurts was higher than for the control (p ≤ 0.05). Therefore, the three probiotic strains with cholesterol-lowering properties had potential in future yoghurt production.

Construction and Analysis of Food-Grade Lactobacillus kefiranofaciens β-Galactosidase Overexpression System

Lactobacillus kefiranofaciens contains two types of β-galactosidase, LacLM and LacZ, belonging to different glycoside hydrolase families. The difference in function between them has been unclear so far for practical application. In this study, LacLM and LacZ from L. kefiranofaciens ATCC51647 were cloned into constitutive lactobacillal expression vector pMG36e, respectively. Furtherly, pMG36n-lacs was constructed from pMG36e-lacs by replacing erythromycin with nisin as selective marker for food-grade expressing systems in Lactobacillus plantarum WCFS1, designated recombinant LacLM and LacZ respectively. The results from hydrolysis of o-nitrophenyl-β-galactopyranoside (ONPG) showed that the β-galactosidases activity of the recombinant LacLM and LacZ was 1460% and 670% higher than that of the original L. kefiranofaciens. Moreover, the lactose hydrolytic activity of recombinant LacLM was higher than that of LacZ in milk. Nevertheless, compare to LacZ, in 25% lactose solution the galacto-oligosaccharides (GOS) production of recombinant LacLM was lower. Therefore, two β-galactopyranosides could play different roles in carbohydrate metabolism of L. kefiranofaciens. In addition, the maximal growth rate of two recombinant strains were evaluated with different temperature level and nisin concentration in fermentation assay for practical purpose. The results displayed that 37°C and 20-40 U/ml nisin were the optimal fermentation conditions for the growth of recombinant β-galactosidase strains. Altogether the food-grade Expression system of recombinant β-galactosidase was feasible for applications in the food and dairy industry.

Multifarious cholesterol lowering potential of lactic acid bacteria equipped with desired probiotic functional attributes

Lactic acid bacteria (LAB) isolates possessed functional probiotic attributes, such as high hydrophobicity and autoaggregation ability, coaggregation capability with bacterial pathogens, antimicrobial activity, antioxidant potential, and hypocholesterolemic effects. Selected potential probiotic LAB, i.e. Lactobacillus paracasei M3, L. casei M5, L. paracasei M7, and few others were studied for their ability to lower cholesterol using a number of methods viz. cholesterol assimilation, bile salt deconjugation, cholesterol co-precipitation, cholesterol adhesion to probiotic cell wall, and miceller sequestration of cholesterol. L. casei M5 showed maximum bile salt hydrolase (BSH) activity, and released 57.63 nmol of glycine/min, and was closely followed by LAB isolate M9 which generated 52.12 nmol of glycine/min. Sodium glycocholate was deconjugated by L. casei M5 to produce 27.77 μmol/mL of cholic acid, while other isolates produced 20-26 μmol/mL of cholic acid. Cholesterol was assimilated significantly by isolate M6 (82.15%) and L. casei M5 (76.51%). L. casei M5 showed higher cholesterol co-precipitation ability (50.16 μg/mL) as compared to other LAB isolates (33-44 μg/mL). Miceller cholesterol concentration was reduced maximally by LAB isolate M8 (87.5%), followed by isolates M5 (84.75%), M9 (84%), M10 (80%), and M37 (79%). Higher cell wall adhesion of cholesterol was realized by L. casei M5 (42.48 μg/mL) than other LAB isolates (30-40 μg/mL). Selected LAB probiotics demonstrated short chain fatty acid (acetate, propionate, and butyrate) producing ability, yet another way of probiotics-mediated cholesterol lowering.