Exploring probiotic benefits and competence of Streptococcus thermophilus strain M2 isolated from the yogurt-based beverage mattha

The increasing interest in functional foods has encouraged the search for new lactic acid bacteria (LAB) with singular characteristics, including technological and probiotic properties, present in natural sources. The present research aimed to isolate and in vitro characterize the probiotic potential of LAB isolated from artisanal goat cheese. In addition, the acidifying and proteolytic capacity of the strains were evaluated in order to develop a functional dairy product. Fifty strains, presumptively identified as LAB, were isolated from artisanal goat cheese. From them, seventeen strains were selected for identification through Matrix-Assisted Laser Desorption Ionization-Time of Flight (MALDI-TOF) Mass Spectrometry (MS) and 16S gene sequence. None of the tested strains showed hemolytic ability, while all strains showed at least 76% of survival to low pH and conjugated bile salts. Hydrophobicity and auto-aggregation values varied among LAB with ranges between 15.5 ± 1.8 to 84.7 ± 3.2, and 4.72% to 59.2%, respectively. Selected LAB were capable of adhering to intestinal mucus in a range of 5.08 to 6.90 Log CFU/mL. Remarkably, eight strains showed high bile salt hydrolase activity. Autochthons strains were able to grow and acidify milk after 24 h. Besides, proteolytic activity showed a range between 10 and 151 mmol/L amino acids. PCA analysis and technological properties allow us to propose Lactiplantibacillus plantarum CB5, CB8 and Lentilactobacillus parabuchneri CB12 strains as potential probiotic starter cultures. The isolation of new LAB strains with demonstrated functional properties is of interest to academic institutions and the food industry as it allows the design of indigenous dairy cultures with added probiotic and technological properties.

Screening lower high cholesterol and secretion of bile salt hydrolase (BSH) from yeast strains, and study the environmental factors for increasing the activity of BSH, then investigate the mechanism of cholesterol lowering. We obtained two yeasts to lower cholesterol by high-throughput screening technology and o-phthalaldehyde : strain K1 and strain M3 are Kluyveromyces marxianus, are the highest rate of cholesterol-reducing strains by far, the lower cholesterol rates were 68.14% ~ 70.34% , 80.51% ~ 99.12%. The two yeasts can secretion BSH in the metabolic process with the Oxford cup method, and the BSH activity is proportional to the rates of cholesterol-reducing. Strain M3 has a higher BSH production capacity than strain K1, and high cholesterol-lowering effect. That indicating efficient yeast strains to lower cholesterol production is due to their abundant or high activity BSH. The BSH secretion of strain K1 and strain M3 demonstrated a key enzyme in cholesterol-lowering effect for the first time. BSH can hydrolyze conjugated bile salt and free bile salt, which can precipitate with cholesterol state, to reduce the effect of cholesterol. To aim directly at 4 major factors can affect the synthesis of BSH, the fermentation conditions of strain M3 producing BSH highly were determined with four factors and three levels［L9(34)］orthogonal experiment: fermentation temperature is 32 °C, fermentation time is 24h, the initial pH of medium is 6.0, inoculums is 3%. The activity of BSH secreted by Strain M3 increased 50% in the optimization of fermentation conditions. Strain K1 and M3 fermented milk with excellent performance, we could research and develop functional fermented dairy products and micro-ecology preparation, by using the characteristics of efficient to lower cholesterol and complementary advantages of lactose fermentation performance of the two strains.

Exopolysaccharides (EPSs), produced by lactic acid bacteria (LAB), play a crucial role in enhancing the texture and stability of yoghurt by forming a protective matrix that helps to maintain its rheological and sensory characteristics. The search for a dairy alternative for the lactose-intolerant populace is a necessity, and the use of probiotic LAB and their EPS to formulate fermented coconut beverage (FFCB) will be of added advantage. The production and characterization of EPS from a LAB strain isolated from yoghurt, its probiotic and antioxidant potential, and its application in the production of probiotic FFCB were investigated. The EPS produced by the isolate was characterized using a scanning electron microscope (SEM), high-performance liquid chromatography, Fourier transform infrared (FT-IR) spectroscopy, and energy-dispersive X-ray. The antioxidant potential of the EPS was determined. The isolate probiotic potential, such as tolerance to low pH, bile salts, gastric pH, autoaggregation, coaggregation, antimicrobial potential, and antibacterial activity, was evaluated, and the isolate was identified using 16S rRNA. The LAB strain and the EPS were used for the formulation of probiotic FFCB, and the proximate mineral composition of the enriched yoghurt was determined. Isolate W3 produced 6204.50 mg/L EPS. The EPS produced by the LAB was spherical with a coarse surface. Hydroxyl, carboxyl, and α-pyranose were the major functional groups present in the EPS. Eight monosaccharides were present in glucose, which has the highest molar ratio. The EDX spectra ascertain the presence of carbon, oxygen (carbohydrate), and other elements. The purified EPS exhibited antioxidant activity in a dose-dependent manner. DPPH, FRAP, TAC, and TPC of the EPS ranged from 42.36% to 75.88%, 2.48 to 5.31 μg/mL, 1.66 to 3.57 μg/mL, and 1.42 to 2.03 μg/mL, respectively. The LAB strain exhibited moderate tolerance to low pH, bile salts, gastric juice, good autoaggregation (13.33%), coaggregation (0%–59.09%) with E. coli, and varied sensitivity to different antibiotics used. The isolate is hemolysis, deoxyribonuclease (DNase), and lecithinase negative, possesses characteristics of probiotics, and could have the ability to confer health benefits. The LAB strain has a 100.0% pairwise identity to Pediococcus acidilactici. The FFCB has pH, lactic acid, specific gravity, total soluble solids (TSSs), and vitamin C content ranging from 5.81 to 6.8, 10.8 to 55.8 mg/L, 0.910 to 1.394 kg/m3, 0.136 to 0.196 °Bx, and 0.26% to 0.66%. The formulated beverage fermented with a commercial starter had the highest lactic acid at Day 7 of storage. The FFCB sample with the commercial starter and the probiotic strain had the highest ash and crude fiber content (1.3%, 0.68%). The FFCB fortified with EPS showed the highest protein content (4.6%). The formulated yogurt samples fortified with the highest concentration of EPS had the highest calcium content after 7 days of storage (162.31 ± 0.01a). In conclusion, EPS produced by Pediococcus acidilactici was a heteropolymeric EPS with good antioxidant activity, and the LAB strain exhibited a good starter for producing FFCB enriched with EPS. The FFCB has good nutritional characteristics and could serve as a functional and natural nutraceutical food for the lactose intolerance population.

There are many functional characteristics of exopolysaccharides (EPS) produced by lactic acid bacteria in fermented dairy products. In this study, 2 EPS-producing strains of Lactobacillus delbrueckii ssp. bulgaricus and 2 Streptococcus thermophilus strains were isolated from commercial and rural yoghurts and they were inoculated into whey and their effects on EPS production and viscosity of whey were monitored. Two pH applications (adjusted pH and free pH) and 3 incubation temperature (42, 36 and 42/36oC) were performed. pH of samples was significantly affected by starter culture strains, pH adjustment and incubation temperature (P < 0.01). Generally counts of L. delbrueckii ssp. bulgaricus were found higher than of S. thermophilus (P < 0.05). Viable cell counts were significantly higher, in pH-adjusted samples and 42oC samples, than their relevants (P < 0.01). Higher concentrations of EPS were observed in pH-adjusted media than that in pH-free media (P < 0.01). Also 2-step (42/36oC) and lower (36oC) incubation temperature caused an increase in EPS production. Viscosity of samples greatly influenced from their EPS contents. The highest EPS concentration (676 mg/L) and viscosity (6.37 mPa.s) was determined in the sample that inoculated with S. thermophilus ST3 strain, incubated at 42/36oC with pH-adjustment. Key words: Lactic acid bacteria, exopolysaccharide, whey.

Background: The global health threat posed by antimicrobial resistance (AMR) has created an urgent need for developing alternative treatment methods. Probiotics, especially Lactic Acid Bacteria (LAB), are gaining interest in this context, as they demonstrate health-enhancing effects and potent antimicrobial activities. The intestines of goats could be a potential origin for developing new probiotics applications in animal feed and human health. Hence this study was carried out to determine the antibiotic resistance profiles of LAB and pathogens within the intestines of Nigerian dwarf goats (Capra aegagrus hircus), the antimicrobial activity of LAB against resident MDR pathogens, and subsequent identification of bioactive LAB isolated from goat faeces in Nigeria as potential probiotics in animal feed and human health.&#x0D; Method: Selective isolation of the LAB was carried out using de Mann Rogosa Sharpe (MRS) agar while enteric pathogens were isolated on MacConkey agar. Preliminary identification was carried out based on Gram reaction, and morphological, colonial, and biochemical characteristics of each isolate. Antibiotic susceptibility profiles of all isolates were determined using the Kirby-Bauer disc diffusion method. The agar overlay method was used to test the most resistant LAB isolates for antimicrobial activity against enteric pathogens. Selected LAB isolates were identified by 16SrRNA sequencing. &#x0D; Results: The antibiotics susceptibility profile showed that a majority (77%) of LAB isolates and minimal (҇≤10%) of enteric pathogens demonstrated resistance to at least three classes of antibiotics, indicating a pattern of multi-drug resistance. Over half (62%) of these LAB isolates displayed significant antimicrobial activity against at least five of the resident-resistant pathogens, illustrating their potential role in controlling these pathogens. The sequencing results identified the most active LAB isolates, revealing a mix of strains including Pediococcus lolli (46%), Pediococcus pentosaceus (23%), Weissella confusa (8%), Enterococcus faecium (8%), Enterococcus hirae (8%), and Lactobacillus sanfranciscensis (8%).&#x0D; Conclusion: The discovery of a diverse range of LAB strains in goat intestines with significant antimicrobial activity against resident enteric pathogens is valuable. This finding suggests the potential use of these bacteria as natural alternatives to traditional antibiotics, especially in the context of growing AMR in animal husbandry.

Probiotic Potential and Partial Characterizations of Exopolysaccharide from Lactic Acid Bacteria Isolated from Camel Rumen and Dairy Products.

Twenty two strains of lactic acid bacteria (LAB) were isolated from 30 samples of commercial Nigerian bottled yoghurt (produced on a small scale). Isolates were phenotypically characterized and their technological properties such as acidification, exopolysaccharides (EPS) production, enzymatic activities, biogenic amine production and bacteriocin production were studied following standard procedures. The population of LAB in the yoghurt samples varied between 0.00 and 6.63 log cfu ml-1. The pH and titratable acidity ranged from 3.80 to 4.48 and 0.73 to 1.78% lactic acid respectively. The isolated LAB strains belonged to Lactobacillus, Lactococcus, Leuconostoc, Streptococcus and Enterococcus genera. Thirteen strains showed proteolytic activity while four strains showed high lipolytic activity. The LAB strains exhibited medium to low acidification activities. About 77% of the LAB strains produced EPS. Six strains produced biogenic amines. Seven strains showed antagonistic properties due to organic acid against indicator organisms (Staphylococcus aureus, Klebsiella pneumoniae, Escherichia coli and Proteus vulgaris) while two strains (Enterococcus faecalis and Lactococcus cremoris) produced additional inhibitory substances againstK. pneumoniae. The results revealed that the assayed commercial Nigerian bottled yoghurts contain several LAB species and genera different from Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus. The production of biogenic amine by some of the LAB strains is undesirable in yoghurt. The technological properties of the LAB associated with the fermented milk produced on a small scale will help in the selection and development of beneficial strains as starter or adjunct cultures. Key words: Yoghurt, lactic acid bacteria, technological properties, strain selection.

Cereus jamacaru DC. (mandacaru) fruit as a source of lactic acid bacteria with in vitro probiotic-related characteristics and its protective effects on Pediococcus pentosaceus during lyophilization and refrigeration storage

BackgroundThroughout Africa, food fermentations are still driven by indigenous microorganisms which influence the nutritional, organoleptic and safety of the final products. However, for improved safety, consistent quality and beneficial health effects, a trend has emerged which involves the isolation of indigenous strains from traditional fermented products to be used as functional starter cultures. These functional starter cultures possess inherent functional characteristics and can contribute to food quality and safety by offering one or more organoleptic, nutritional, technological or health advantage (probiotics). With the aim of selecting potential probiotic starter cultures, Lactobacillus fermentum strains isolated from fermented millet dough were investigated for technological properties and probiotic traits in-vitro.ResultsA total of 176 L. fermentum strains were assessed for technological properties including rate of acidification, exopolysaccharide production and amylase activity. Following this, 48 strains showing desirable technological properties were first screened for acid resistance. Sixteen acid resistant strains were assessed for additional probiotic properties including resistance to bile salts, bile salt hydrolysis, antimicrobial property, haemolysis and antibiotics resistance. L. fermentum strains clustered into 3 groups represented by 36 %, 47 % and 17 % as fast, medium and slow acidifiers respectively. About 8 %, 78 % and 14 % of the strains showed strong, weak and no exopolysaccharides production respectively. Amylase activity was generally weak or not detected. After exposure of 48 L. fermentum strains to pH 2.5 for 4 h, 16 strains were considered to be acid resistant. All 16 strains were resistant to bile salt. Four strains demonstrated bile salt hydrolysis. Antimicrobial activity was observed towards Listeria monocytogenes and Staphylococcus aureus but not E. coli and Salmonella enteritidis. Lactobacillus fermentum strains were generally susceptible to antibiotics except 6 strains which showed resistance towards streptomycin, gentamicin and kanamycin.ConclusionIn vitro determination of technological and probiotic properties have shown strain specific difference among L. fermentum strains isolated from fermented millet dough. Sixteen (16) L. fermentum strains have been shown to possess desirable technological and probiotic characteristics in vitro. These strains are therefore good candidates for further studies to elucidate their full potential and possible application as novel probiotic starter cultures.

Exploring probiotic potential and antimicrobial properties of lactic acid bacteria from cow's milk

BackgroundProbiotics are live microorganisms that effectively combat foodborne pathogens, promoting intestinal health when consumed in sufficient amounts. This study evaluated the probiotic potential and safety of lactic acid bacteria isolated from selected Ethiopian traditional fermented foods and beverages (Kotcho, Bulla, Ergo, Cabbage-Shamita, Borde, and Bukuri). To assess the isolates’ probiotic activity, tolerance, and survival rate under various stressful conditions, including low pH, intestinal inhibitory substances, salt concentration, bile salt, and simulated gastric/intestinal juice. The isolates were also tested for antagonistic activities against common bacterial and fungal pathogens (Staphylococcus aureus, Salmonella Typhimurium, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Candida albicans) and safety (auto-aggregation, co-aggregation, cell source hydrophobicity, hemolytic activity, DNase, and antibiotic susceptibility). The best probiotic lactic acid bacteria (LAB) were characterized to species level following standard MALDI TOF/mass spectrometry analysis.ResultsA total of 125 potentially probiotic LAB were isolated of which 17 (13.60%) isolates survived low pH (2, 2.5, and 3), bile salt (0.3%), intestinal inhibitory chemicals (phenol, bile, low acidity, pepsin, and pancreas), and simulated gastro-intestinal settings with near 60–94% survival rate. In addition, 11 best LAB isolates were further screened based on additional screening including their antimicrobial efficacy, preservative efficiency, bacteriocin production besides resistance to low acid and bile salts, and survival potential under simulated gastrointestinal conditions. All 11 LAB isolates were resistant to ampicillin, vancomycin, gentamicin, kanamycin, clindamycin, and chloramphenicol, while they were susceptible to streptomycin and tetracycline. The MALDI TOF mass spectrometry analysis result of efficient probiotic LAB grouped them under the genus Pediococcus, Enterococcus, and Lactococcus including Pediococcus pentosaceus, Enterococcus faecium, Lactococcus lactis, and Pediococcus acidilactici.ConclusionEthiopian traditional fermented foods and beverages are good sources of promising probiotic lactic acid bacteria. These isolates could serve as potential starter cultures and bio-preservative for the enhancement of the shelf life of foods. This study established the groundwork for the selection of excellent probiotics for the development and application of LAB for antibacterial action, starter culture production, and preservation activities.

Abstract. Fidien KA, Manguntungi B, Sukmarini L, Mustopa AZ, Triratna L, Fatimah, Kusdianawati. 2021. Diversity analysis, identification, and bioprospecting of Lactic Acid Bacteria (LAB) isolated from Sumbawa horse milk. Biodiversitas 22: 3333-3340. Sumbawa horse milk has a probiotic potential because of the presence of Lactic Acid Bacteria (LAB). The LAB present in Sumbawa horse milk has been reported to have antimicrobial activities against pathogenic bacteria, including Staphylococcus epidermidis, Staphylococcus aureus, Escherichia coli, and Vibrio cholerae. However, the potential of LAB from Sumbawa horse milk as antioxidant and antidiabetic is still unexplored. Studies related to the diversity of indigenous bacteria in Sumbawa horse milk based on metagenomic analysis have not been widely studied either. Therefore, this study aimed to determine the diversity of species of indigenous bacteria in Sumbawa horse milk and to identify LAB bioprospecting from Sumbawa horse milk. The diversity of indigenous bacterial species was investigated by the 16S rRNA gene-targeted metagenomic approach from bacterial DNA isolated from Sumbawa horse milk. The identification of LAB was also carried out by the 16S rRNA gene identification method. LAB bioprospecting on antioxidant activity was determined using the DPPH method, while the antidiabetic activity was measured using the ?-glucosidase inhibition assay. The diversity analysis of indigenous bacteria based on 16S rRNA gene-based metagenomic revealed at least 7 phyla were relatively abundant in Sumbawa horse milk. The greatest abundance was shown by the phylum Proteobacteria (0.641%) and Firmicutes (0.327%). Enterococcus durans (39.01%) was the species that had the highest abundance in Sumbawa horse milk, followed by Lactococcus garvieae (30.13%) and Lactococcus lactis (19.85%). Moreover, based on the identification of the 16S rRNA gene, eight LAB isolates had similarities to bacterial strains, including Enterococcus faecium DSM 20477, E. faecium NBRC 100486, E. faecium ATCC 19434, E. durans 98D, E. faecalis ATCC 19433, E. faecalis NRBC 100480, Lactococcus lactis subsp. hordniae NBRC 100931 and L. garvieae JCM 10343 with similarity levels of more than 98%. In terms of LAB bioprospecting, the antioxidant assay showed the highest DPPH radical binding activity by L. garvieae L.22PR (43%). Meanwhile, the highest inhibitory activity of ?-glucosidase was shown by E. faecium G.6PR (45%).

The Sumbawa buffalo (Bubalus bubalis) is one of the ruminant livestock in Indonesia that not only contributes to fulfilling meat requirements but also milk. Besides containing nutrients that are very beneficial for human health, buffalo milk is also a potential source of lactic acid bacteria (LAB) with technological and functional properties. Lactic acid bacteria have been utilized as starter cultures in various fermented products. This study aimed to isolate LAB from Sumbawa buffalo milk and to identify the potential isolate as a starter culture. The screening of LAB as a starter culture was based on some technological properties, including proteolytic activity, lipolytic activity, exopolysaccharide (EPS) production, antibacterial activity, antibiotic sensitivity, hemolytic activity, and acidification activity Data were analyzed statistically using one-way ANOVA and Tukey’s post hoc test at a 5% significance level. A total of 21 isolates were isolated from fresh buffalo milk, with a LAB total was 4.7x105 CFU.mL-1. All the isolates were characterized as Gram-positive with cocci-shaped. The SA8 isolate was selected as the most potential candidate as a starter culture because it has fulfilled the criteria such as the highest proteolytic activity, the lowest lipolytic activity, producing EPS, potential antagonistic activity against Bacillus cereus, Escherichia coli, and Salmonella Typhi, and sensitivity to cefazolin, intermediate to erythromycin and cinoxacin, non-pathogen, as well as the most rapid acidification activity. The SA8 isolate was identified as Enterococcus lactis with a similarity level of 99.99% towards strain BT159. This indigenous LAB was a potential starter culture of Sumbawa fermented buffalo milk to increase the diversification of products derived from buffalo milk.

Heteropolysaccharides from lactic acid bacteria

Heteropolysaccharides from lactic acid bacteria