High Bile Salt Concentrations Research Articles

Characterization of an inositol-producing Lactobacillus plantarum strain and the assessment of its probiotic potential and antibacterial activity

The compound inositol has many important applications in various fields. However, no information can be obtained on the biosynthesis of inositol by lactic acid bacteria (LAB) so far. In this study, an inositol-producing Lactobacillus plantarum ZJ2868 was isolated and identified, and its probiotic potential and antibacterial activity were assessed. The isolated L.plantarum ZJ2868 strain produced 33.66 ± 0.75 mg/L of inositol. The optimal temperature and pH for the strain growth were 30 °C and 6.0, respectively. This strain could resist high osmotic pressure, and grew well in Man Rogosa Sharpe (MRS) medium with 6% NaCl. It displayed a strong acid resistance, and the number of viable cells was over 93.9% on the conditions of pH 3.0 and 3.5 for 4 h. 59.8% cells could survive at a high bile salt concentration of 0.1% for 1 h. This strain exhibited an obvious inhibitory effect on Pseudomonas fluorescens and Listeria monocytogenes, and was sensitive to amoxicillin and ampicillin. These findings broaden the use of LAB and deepen our understanding of LAB as potential producer of inositol.

Isolation of Lactic Acid Bacteria from Intestine of Freshwater Fishes and Elucidation of Probiotic Potential for Aquaculture Application.

Probiotics play significant roles in enhancing systemic immunity, improving intestinal balance and feed value, enhancing enzymatic digestion, and inhibiting pathogenic microorganisms of freshwater fish. Probiotics from an identical organism's gastrointestinal system promote effective colonization and provide greater benefits than other sources. This study aimed to evaluate the usefulness of probiotic bacteria isolated from the intestines of freshwater fishes for a dietary supplement of freshwater aquaculture. A total of 120 isolates were collected from freshwater fishes of Channa striata, Puntius filamentosus, Oreochromis mossambicus, Cirrhinus mrigala, and Rasbora daniconius. Seven of these isolates exhibited antagonistic activity against fish pathogens: Aeromonas hydrophila, Staphylococcus epidermidis, Staphylococcus aureus, Bacillus cereus, Escherichia coli, and Pseudomonas aeruginosa. Using 16S rRNA gene sequencing analysis, the isolates were identified as Enterococcus sp., Lactococcus lactis, Weissella cibaria, and Limosilactobacillus fermentum. Of these tolerates, L. fermentum URLP18 isolated from C. mrigala exhibited high tolerance to low acidic (pH 2.0) and high bile salt (2%) concentrations, exhibiting a significant hydrophobicity and extracellular enzyme secretions like amylase, protease, and lipase. In vitro evaluations on intestinal mucus indicate that L. fermentum URLP18 have strong adherence capacity, and its survival rate increased after being administered to Artemia nauplii. The results suggest that L. fermentum URLP18 has high probiotic potential and is an effective dietary supplement for freshwater aquaculture.

In vitro Assessment of the Safety and Potential Probiotic Characteristics of Three Bacillus Strains Isolated From the Intestine of Hybrid Grouper (Epinephelus fuscoguttatus♀ × Epinephelus lanceolatus♂).

Probiotics serving as an alternative to the criticized antibiotics mainly focus on improving animal's growth and health. After realizing the dangers posed by diseases that have led to lots of economic losses, aquaculture scientists have sought the usage of probiotics. However, most probiotics are ineffective in eliciting aquatic animals' preferred effects, since they are from non-fish sources. Again, there are even a few marine aquatic probiotics. Given this, a study was conducted to investigate the probiotic potential of the bacteria species isolated from the digestive tract of hybrid grouper (Epinephelus fuscoguttatus♀ × Epinephelus lanceolatus♂). Based on the morphological, biochemical, 16S rRNA sequencing analysis and evolutionary relationships, the isolated species were identified as Bacillus tequilensis GPSAK2 (MW548630), Bacillus velezensis GPSAK4 (MW548635), and Bacillus subtilis GPSAK9 (MW548634), which were designated as GPSAK2, GPSAK4, and GPSAK9 strains, respectively. Their probiotic potentials including their ability to tolerate high bile salt concentration, low pH, high temperatures, adhesion ability (auto-aggregation and cell-surface hydrophobicity), antimicrobial activity and biosafety test, compatibility test, hemolytic activity, and antibiotic susceptibility test were evaluated. While GPSAK2 and GPSAK9 strains were γ-hemolytic, that of GPSAK4 was α-hemolytic. All the isolates were resistant to low pH (1) and higher bile salt concentration (0.5%), showed higher viability ability after higher temperature exposure (80, 90, and 100°C), as well as higher cell-surface percentage hydrophobicity and auto-aggregation. All isolates exhibited positive compatibility with each other, signifying their ability to be used as multispecies. The three strains were susceptible to ampicillin (except GPSAK9, which was resistant), penicillin, kanamycin, ceftriaxone, chloramphenicol, erythromycin, clindamycin, furazolidone (except GPSAK2 and GPSAK9, which were moderately susceptible and resistant, respectively), polymyxin B, vancomycin (except GPSAK9, which was resistant), sulfamethoxazole (except GPSAK9, which was moderately susceptible), amikacin, minocycline, ofloxacin, norfloxacin, doxycycline, neomycin, gentamicin, tetracycline, carbenicillin, midecamycin (except GPSAK9, which was moderately susceptible), ciprofloxacin, piperacillin, and cefoperazone. All isolates demonstrated good antimicrobial activity against four pathogens, viz. Streptococcus agalactiae, Streptococcus iniae, Vibrio harveyi, and Vibrio alginolyticus. The results collectively suggest that Bacillus strains GPSAK2, GPSAK4, and GPSAK9 could serve as potential probiotic candidates that can be used to improve the growth and health status of aquatic animals, especially grouper.

The study of the potential application of nanofiber microcapsules loading lactobacillus in targeted delivery of digestive tract in vitro

The study explores the potential application of the lactic acid bacteria coated in nanofiber microcapsules. Nanofiber microcapsules loading Lactobacillus acidophilus NCFM (L. acidophilus NCFM) were fabricated by electrostatic spinning; the encapsulated efficiency, storage stability, survival in simulated stomach condition, and the stability in water, duodenum stimulated and bile salt of the coated bacteria were determined. The results showed that nanofibers with 209.7 nm mean diameter were produced with 96.7% encapsulation efficiency, and were almost insoluble in water. After 30 d storage at 25 °C, the reduction of L. acidophilus NCFM coated in nanofiber microcapsules was less than that of uncoated L. acidophilus NCFM (0.26 CFU/g vs. 0.86 CFU/g). The nanofiber microcapsules had better resistance to simulated rumen pH and a high concentration of bile salts. In the simulated duodenum pH, the survival rate of L. acidophilus NCFM coated in nanofiber microcapsules in pH2 was higher than that in pH3. In summary, these results demonstrated that nanofiber microcapsules with L. acidophilus NCFM have a good shape, tiny size and great stability in water and storage at room temperature, great encapsulated efficiency for the bacteria, and could resist stomach pH but release the bacteria at duodenum pH.

Autochthonous Lactobacillus paracasei subsp. paracasei strains isolated from Caciocavallo cheese: identification and in-vitro investigation on potential probiotic and functional properties

Background: In recent years consumers, due to the growing interest for functional foods, have put particularly attention on products enriched with probiotic lactic acid bacteria for their ability to give human benefit by their assumption. Microorganisms to be considered as probiotic should be able to survive to gastrointestinal juices and colonize the intestinal tract to provide benefits to human health. The aim of the study consisted of the in vitro investigation of novel LAB strains, isolated during cheesemaking and ripening of Caciocavallo cheese, and on their probiotic potential for food application. Methods: In order to select potential probiotic bacteria, LAB isolates were preliminarily screened for their survival to simulated gastro-intestinal transitand assayed for other activities of probiotic and functional interest. Thanks to promising attitude as potential probiotics, four strains were tested to evaluate their adhesion ability on Caco-2 cell lines used as intestinal cell model. Microbiological data were analysed by one-way analysis of variance (ANOVA). Comparisons of means were carried out using post-hoc Tukey’s test. For vitro adhesion experiments, statistical significance was evaluated by Kruskal-Wallis test for equal medians. Results: Twenty-five LAB, presumptively identified as Lactobacillus spp., were isolated from cheese during 60 days of ripening and screened for their survival to simulated gastrointestinal transit. Sixteen isolates that showed a survival rate ≥85% were identifiedas 10 different profiles of Lb. paracasei subsp. paracasei. The 10 strains tolerated high concentration of bile salts by Minimal Inhibitory Concentration and growth rate assays and showed susceptibility or moderate susceptibility against antibiotics of human and veterinary importance, except for the resistanceto the class of aminoglycoside antibiotics. Eight out 10 strains showed in vitro cholesterol-lowering ability, whereas all strains showed antioxidant activity of their cell-free supernatants. Moreover, the four strains with highest survival to simulated gastrointestinal transit showed the ability to adhere to Caco-2 cells. Conclusion: The results suggest that some strains may be effective probiotics to be use as tool to design probiotic dairy products after confirmation probiotic activities in further in vivo studies. Findings of the present study suggest that four strains showed good or strong adherent ability on Caco-2 cell monolayer, that is one of prerequisite that probiotic bacteria must have to perform their functional properties. Keywords: adhesion, antioxidant activity, bile salts, cholesterol assimilation, dairy products, gastrointestinal resistance, probiotic lactobacilli.

Determination of antimicrobial, pH, bile salt, and gastric juice tolerance properties of Lactobacilli isolated from human milk

Human milk is a complex biological fluid, and a source of nutrients and probiotics which plays a vital role in the growth and development of infants. Probiotics are helpful bacteria which are good for human health. The primary bacterial genera which are gaining status as probiotics are Lactobacillus, Lactococcus, and Bifidobacterium. The present work aimed to isolate, identify, and determine the probiotic potential of Lactobacillus bacteria from human milk. A total of 70 samples of human milk were collected from different lactating mothers. The milk samples were inoculated on the De Man, Rogosa, and Sharpe (MRS) agar plates to observe the growth of Lactobacillus bacteria. The bacteria were identified based on their morphology, culture characteristics, and biochemical properties. Isolated bacteria were evaluated for probiotic properties in which, tolerance to acidic pH, bile salts, and gastric juice as well as antibacterial activity and antibiotic susceptibility were determined. Out of the 70 milk samples, 57 were positive for Lactobacillus. Out of the positive sample, 10.5% of the samples tolerated acidic pH and high bile salt concentration, but a significant difference was obtained for gastric juice. In the antibacterial activity, Pseudomonas showed no action against Lactobacillus. In antibiotic susceptibility, the test isolates were resistant to penicillin. The present work proved the presence of beneficial bacteria in the human milk. Isolated Lactobacillus exhibited significant antibacterial activity against pathogenic bacteria, and tolerance to acidic pH, bile salt, and gastric juice. Therefore, human milk could be a good source of probiotics for infants.

In Vitro Assessment of Probiotic Potential of Saccharomyces Cerevisiae DABRP5 Isolated from Bollo Batter, a Traditional Goan Fermented Food.

Bollo is a traditional Goan fermented food in which coarse wheat/wheat and finger millet is leavened with toddy. We here isolated 42 yeast strains from Bollo batter. Initial screening of the isolates with probiotic properties yielded four yeast isolates (DABRP1, DABRP2, DABRP5 and DABRP12). These isolates exhibited tolerance to high bile salt concentration and acidic pH and resistance to various antibiotics, which indicated their probiotic nature. All these yeast isolates were identified as Saccharomyces cerevisiae through D1D2-LSU-rDNA sequencing. These yeast isolates also showed higher percent hydrophobicity towards chloroform followed by n-hexadecane and o-xylene indicating their mucosal surface-adhesive property. To evaluate the safety of the isolates for them to be called as generally recognized as safe, the pathogenic behavior of the isolates determined through the in vitro hemolysis assay and evaluation of DNase and gelatinase activities. None of the isolates exhibited hemolysis or produced DNase or gelatinase and thus were considered potentially safe. In terms of beneficial effects, the most potent isolate S. cerevisiae DABRP5 showed antibacterial activity against the test pathogens. It also showed excellent antioxidant activity with DPPH free radical scavenging activity of 68.85 ± 0.69%, anti-inflammatory activity with 60.39 ± 0.34% inhibition of protein denaturation, and antidiabetic activity with 71.75 ± 0.45% inhibition of α-amylase activity. The isolate produced α-amylase, lipase, and β-galactosidase. The probiotic potential of the isolate S. cerevisiae DABRP5 was similar to that of the reference strain (Saccharomyces boulardii CNCM I-745) used in this study. The results thus indicate that yeast isolates from Bollo batter have probiotic potential.

Ameliorative Function of a Probiotic Bacterium, Lactobacillus rhamnosus MR1 on Acute Iron Toxicity in Rats

Overuse of iron supplements can lead to an acute inflammation of the gastrointestinal tract. This study investigates the ameliorative and prophylactic effects of a probiotic bacterium, L. rhamnosus MR1, on acute iron poisoning in rats. In this study, a probiotic strain was isolated from yogurt and characterized for its probiotic properties, including antibiotic-resistant, bile salt (BS) and acid resistance, iron tolerance, cell hydrophobicity of the bacterial cells. The anti-inflammatory effect of strain MR1 was studied on the iron exposed-Caco-2 cell line. In vivo experiments were conducted for the assessment of survival in rats overdosed with treatment. These findings indicate high bacterial tolerance in acidic conditions, high concentrations of bile salts, and iron. The anti-inflammatory effects of strain MR1 were confirmed by decreasing the concentration of pro-inflammatory cytokine IL-8 and increasing anti-inflammatory cytokine IL-4 in treated groups. Prophylactic and acute effects of strain MR1 in rats caused a significant reduction in intestinal iron poisoning by 50 % during 6 h. Prophylactic regimen by L. rhamnosus MR1 increased the viability of about 33% in acutely poisoned rats. Since no report is found in the current literature about the effect of probiotic supplements on iron's acute toxicity, these interesting results can provide a useful background for further studies on dietary supplements.

Functional and Genomic Characterization of Ligilactobacillus salivarius TUCO-L2 Isolated From Lama glama Milk: A Promising Immunobiotic Strain to Combat Infections.

Potential probiotic or immunobiotic effects of lactic acid bacteria (LAB) isolated from the milk of the South American camelid llama (Lama glama) have not been reported in published studies. The aim of the present work was to isolate beneficial LAB from llama milk that can be used as potential probiotics active against bacterial pathogens. LAB strains were isolated from llama milk samples. In vitro functional characterization of the strains was performed by evaluating the resistance against gastrointestinal conditions and inhibition of the pathogen growth. Additionally, the adhesive and immunomodulatory properties of the strains were assessed. The functional studies were complemented with a comparative genomic evaluation and in vivo studies in mice. Ligilactobacillus salivarius TUCO-L2 showed enhanced probiotic/immunobiotic potential compared to that of other tested strains. The TUCO-L2 strain was resistant to pH and high bile salt concentrations and demonstrated antimicrobial activity against Gram-negative intestinal pathogens and adhesion to mucins and epithelial cells. L. salivarius TUCO-L2 modulated the innate immune response triggered by Toll-like receptor (TLR)-4 activation in intestinal epithelial cells. This effect involved differential regulation of the expression of inflammatory cytokines and chemokines mediated by the modulation of the negative regulators of the TLR signaling pathway. Moreover, the TUCO-L2 strain enhanced the resistance of mice to Salmonella infection. This is the first report on the isolation and characterization of a potential probiotic/immunobiotic strain from llama milk. The in vitro, in vivo, and in silico investigation performed in this study reveals several research directions that are needed to characterize the TUCO-L2 strain in detail to position this strain as a probiotic or immunobiotic that can be used against infections in humans or animals, including llama.

Microencapsulation of Probiotics by Exopolysaccharides-sodium Alginate and Evaluation of their Survival in Simulated GI Conditions

Background: The viability of the probiotics reduces because of the high acid and bile salt concentrations present in the stomach. Probiotic cultures can be protected during processing, storage and passage of the probiotic product through the gastrointestinal tract by the technique of microencapsulation. Objective: In the present study, Exopolysaccharides (EPS) and sodium alginate are incorporated in a different ratio to form the encapsulation matrix. They have also been checked for improving the viability of lactic acid bacteria in simulated GI conditions. Methods: EPS were isolated from a reference strain of L. acidophillus and the two strains P8 and Cu3 isolated from pumpkin and cucumber. Microencapsulated beads were formed using a different combination of EPS and sodium alginate and were analysed in terms of viability, bile tolerance, acid tolerance, survival in gastrointestinal conditions, and antibiotic susceptibility conditions. Results: The results indicated that the increasing concentration of EPS has significantly increased the survival of microencapsulated probiotic in simulated gastrointestinal conditions. The treatment T4 was found to be the best for all the tested conditions. Conclusion: This study has shown the potential application of EPS in microencapsulation to protect probiotics against the adverse condition of the gastrointestinal tract.

In vitro assessment of some probiotic properties and inhibitory activity against Yersinia ruckeri of bacteria isolated from rainbow trout Oncorhynchus mykiss (Walbaum)

In the present study, we isolated bacteria from intestines of healthy rainbow trout, screened for their probiotic properties, and inhibitory activity against Y. ruckeri. A total of 21 out of 541 isolates from the intestine of adult rainbow trout (∼ 200–350 g), showed inhibition zones around at least one Y. ruckeri strains tested. Six of them were selected due to their ability to inhibit all the pathogenic strains on solid medium. They were identified as B. amyloliquefaciens 131and Paenibacillus spp (code 134, 1cc, 1d, 1k, and 2cc). Excluding the isolate 1k, selected strains were able to inhibit Y. ruckeri strains at 22 and 15 ± 0.5 °C when they were simultaneously cocultured, however, they did not show inhibition at 12 ± 0.5 °C. A pre incubation process of the selected strains for 24 h prior to co-culture with strains of Y. ruckeri enabled them to inhibit target pathogens at the lowest temperature tested. Furthermore, probiotic candidates survived to high concentrations of rainbow trout bile salts and acidic conditions. Selected bacteria were also able to produce amylolitic, proteolytic and lipolytic enzymes and showed variable hydrophobic values. Biosafety assays, performed by oral and intraperitoneal infection using B. amyloliquefaciens 131 and Paenibacillus spp (code 134, 1cc, 1d, 1k, and 2cc), showed no pathogenic effect in rainbow trout during 20-day experiment. Therefore, selected strains showed potential characteristics that are required to be evaluated in vivo for their possible subsequent use as probiotics in rainbow trout aquaculture.

Biochemical and Molecular Characterization of Lactic Acid Bacteria (LAB) Isolated from Fermented Pulses

Pulses are excellent source of protein, fiber and other key nutrients. Fermented pulse-based products are routinely used in many parts of India. In this study, an attempt has been made to isolate potent probiotic lactic acid bacteria from traditionally fermented Vigna radiata (mung beans) and Cajanus cajan (pigeon pea). Fermented seed samples of both the pulses were used for the isolation of lactic acid bacteria using Lactobacilli selection medium de Man, Rogosa and Sharpe. Twenty colonies were randomly selected, based on differential colony morphology. Only Gram-positive and catalase-negative isolates were further propagated for biochemical characterization. The isolates obtained showed different growth patterns at acidic conditions (pH 2, 3 and 4) and at high bile salt concentration (0.5% and 1.0%). Most of the isolates showed promising results in antibiotic resistance assay and cell surface hydrophobicity test. Three potent isolates were identified as Pediococcus pentosaceus (RBS1), Enterococcus durans (RBS3) and Pediococcus pentosaceus (RBS10) using 16S rDNA sequencing.

STUDI IN VITRO BAKTERI ASAM LAKTAT KANDIDAT PROBIOTIK DARI MAKANAN FERMENTASI INDONESIA

Indonesia has a rich variety of fermented foods. The lactic acid bacteria contained in such fermented foods can act as probotics providing positive effects on digestive health. Lack of information about the characteristics of the native LAB caused insufficient use of them in functional food products. The purpose of this study was to carry out in vitro selection of potential probiotics of lactic acid bacteria isolated from non-dairy fermented foods i.e. pickle, cassava tape, terasi and dadih. The probiotic property tests are acid and bile salt tolerance assays, hydrophobicity test, adhesion test and coaggregation test. LAB isolates passing all tests indicate that they are potential as probiotics. This study obtained 4 LABs having probiotics properties by in vitro tests, i.e. L. plantarum LIPI12-2-LAB004 from pickle (Yogyakarta), L. plantarum LIPI12-2-LAB031 from cassava tape (Yogyakarta), L. plantarum LIPI13-2-LAB011 from terasi (Bali), and L. plantarum LIPI13-2-LAB087 from terasi (Solok). The four LAB were able to survive high acid and bile salt concentrations above 85%, had hydrophobicities above 95%, capable of adhering to solid surfaces for 24 hours, and were able to co-aggregate with other LAB isolates.

Concentration-dependent effects of sodium cholate and deoxycholate bile salts on breast cancer cells proliferation and survival.

Bile acids (BAs) are bioactive molecules that have potential therapeutic interest and their derived salts are used in several pharmaceutical systems. BAs have been associated with tumorigenesis of several tissues including the mammary tissue. Therefore, it is crucial to characterize their effects on cancer cells. The objective of this work was to analyse the molecular and cellular effects of the bile salts sodium cholate and sodium deoxycholate on epithelial breast cancer cell lines. Bile salts(BSs) effects over breast cancer cells viability and proliferation were assessed by MTS and BrdU assays, respectively. Activation of cell signaling mediators was determined by immunobloting. Microscopy was used to analyze cell migration, and cellular and nuclear morphology. Interference of membrane fluidity was studied by generalized polarization and fluorescence anisotropy. BSs preparations were characterized by transmission electron microscopy and dynamic light scattering. Sodium cholate and sodium deoxycholate had dual effects on cell viability, increasing it at the lower concentrations assessed and decreasing it at the highest ones. The increase of cell viability was associated with the promotion of AKT phosphorylation and cyclin D1 expression. High concentrations of bile salts induced apoptosis as well as sustained activation of p38 and AKT. In addition, they affected cell membrane fluidity but not significant effects on cell migration were observed. In conclusion, bile salts have concentration-dependent effects on breast cancer cells, promoting cell proliferation at physiological levels and being cytotoxic at supraphysiological ones. Their effects were associated with the activation of kinases involved in cell signalling.

Pediococcus acidilactici P25 Protected Caenorhabditis elegans against Enterotoxigenic Escherichia coli K88 Infection and Transcriptomic Analysis of Its Potential Mechanisms.

Enterotoxigenic Escherichia coli (ETEC) K88 is a zoonotic pathogen. Previous studies have shown that lactic acid bacteria (LAB) have great potential in promoting health and resisting pathogenic infections; however, relatively little research has been done on the Pediococcus genus of LAB. This study is aimed at exploring the mechanisms imparted by Pediococcus acidilactici P25 against ETEC K88 in Caenorhabditis elegans. The probiotic performance of P25 was investigated in vitro. Colonization of K88 in the intestinal tract of C. elegans and abundance of enterotoxin genes were measured. In addition, the transcriptome of C. elegans infected by K88 was analyzed. The result showed that P25 possessed the ability to produce acid, as well as high tolerances to acidic and high bile salt concentrations. Coculture revealed that the growth of ETEC K88 was significantly inhibited by the presence of P25. The median survival of C. elegans fed P25 was 2 days longer than the group infected with K88 alone (P < 0.01). At the same time, the number of colonizing K88 and the abundances of estB and elt were reduced by up to 71.70% and 2.17 times, respectively, by P25. Transcriptome data indicated that P25 affected expression of genes relative to innate immune response and upregulated the abundance of genes in multiple pathways of C. elegans, including peroxisome, longevity, and mitogen-activated protein kinase (MAPK) pathways. These results demonstrated that in the presence of P25, K88 colonization and their expression of enterotoxin genes were reduced. This was accomplished through the alteration of environmental parameters (pH and bile salt) as well as through the promotion of the innate immune response processes, increased longevity, and increased antipathogenic bacteria-related pathways. This work highlights the potential application of P. acidilactici P25 as a probiotic resistant to ETEC K88.

In vitro Probiotic Potential and Safety Evaluation (Hemolytic, Cytotoxic Activity) of Bifidobacterium Strains Isolated from Raw Camel Milk.

The present study was designed to isolate Bifidobacterium strains from raw camel milk and to investigate their probiotic characteristics. Among 35 isolates, 8 were identified as Gram-positive, catalase negative, non-spore forming, non-motile and V or Y shaped rods. B-2, B-5, B-11, B-19 and B-28 exhibited good survival at low pH and high bile salt concentration. Most of the isolates were resistant to nalidixic acid, fusidic acid, polymyxin B, neomycin, streptomycin, gentamicin, rifampicin and kanamycin. Furthermore, the production of exopolysaccharides (EPS), adhesion characteristics, antioxidant properties, antagonistic activities, nitrite reduction and cholesterol assimilation were also studied. Isolate B-11 was chosen because it exhibited most of the probiotic properties among all the tested isolates. It is identified as the member of Bifidobacterium longum group through 16S rRNA gene sequencing and named as B. longum B-11. B. longum B-11 was further selected for in vivo attachment to rat intestine and scanning electron micrographs revealed that attachment of a large number of rods shaped bacterial cell. Our findings suggest that B. longum B-11 processes excellent attributes to be used as potential probiotic in the development of functional probiotic food.

Probiotic properties of a phytase producing Pediococcus acidilactici strain SMVDUDB2 isolated from traditional fermented cheese product, Kalarei

The nutritional challenge faced by the monogastric animals due to the chelation effects of phytic acid, fuel the research on bioprospecting of probiotics for phytase production. Pediococcus acidilactici SMVDUDB2 isolated from Kalarei, exhibited extracellular phytase activity of 5.583 U/mL after statistical optimization of fermentation conditions viz. peptone (1.27%); temperature (37 °C); pH (6.26) and maltose (1.43%). The phytase enzyme possessed optimum pH and temperature of 5.5 and 37 °C, respectively and was thermostable at 60 °C. The enzyme was purified 6.42 fold with a specific activity of 245.12 U/mg with hydrophobic interaction chromatography. The purified enzyme had Km and Vmax values of 0.385 mM and 4.965 μmol/min respectively, with sodium phytate as substrate. The strain depicted more than 80% survival rate at low pH (pH 2.0, 3.0), high bile salt concentration (0.3 and 0.5%), after gastrointestinal transit, highest hydrophobicity affinity with ethyl acetate (33.33 ± 0%), autoaggregation (77.68 ± 0.68%) as well as coaggregation (73.57 ± 0.47%) with Staphylococcus aureus (MTCC 3160). The strain exhibited antimicrobial activity against Bacillus subtilis (MTCC 121), Mycobacterium smegmatis (MTCC 994), Staphylococcus aureus (MTCC 3160), Proteus vulgaris (MTCC 426), Escherichia coli (MTCC 1652) and Lactobacillus rhamnosus (MTCC 1408). The amount of exopolysaccharide produced by the strain was 2 g/L. This strain having the capability of phytate degradation and possessing probiotic traits could find application in food and feed sectors.

Identification and probiotic properties of lactobacilli isolated from two different fermented beverages

PurposeScientific information regarding the microbial content and functional aspects of fermented beverages traditionally produced in certain parts of Europe are scarce. However, such products are believed to have some health benefits and might contain functional bacterial strains, such as probiotics. The aim of the study was to identify such lactic acid bacteria strains isolated from water kefir and, for the first time, from braga, a Romanian fermented beverage made of cereals.MethodsLactic acid bacteria (LAB) were identified to species level based on (GTG)5-PCR fingerprinting and 16S rRNA gene sequencing. Selected strains were screened for their antibacterial activity and probiotic potential.ResultsEight isolates belonging to seven Lactobacillus species were recovered from the two drinks. The identification of LAB involved in the fermentation of braga (Lactobacillus plantarum, Lactobacillus fermentum, and Lactobacillus delbrueckii) is firstly reported here. Five of the Lactobacillus isolates showed antibacterial activity against pathogenic bacteria, including Listeria monocytogenes, Escherichia coli, Staphylococcus aureus, and Salmonella enterica. Moreover, most of them showed a good resistance to pH 2.5 and some survived at high concentrations of bile salts (up to 2%). Two L. plantarum isolates were able to inhibit all the indicator strains, and showed the best viability (about 70%) after a sequential treatment simulating the passage through the gastrointestinal tract.ConclusionBased on the results, the most promising candidates for designing new probiotic products are: L. plantarum BR9 from braga and L. plantarum CR1 from water kefir.

Optimization, kinetics and radioprotective potential of a heteropolysaccharide from L. rhamnosus RVPI.

The probiotic potential of Lactobacillus rhamnosus RVP1 isolated from Sardinella longiceps was investigated in vitro. The bacterium exhibited highest tolerance at low pH, high bile salt concentration and demonstrated good antioxidant activity, hydrophobicity and inhibited both gram-negative and gram-positive indicator bacteria. To aid in process design and to unravel the fermentation kinetics, response surface methodology was devised to optimize the EPS production from L. rhamnosus and mechanistic models were developed to describe the fermentation kinetics. The optimum pH, dextrose and peptone concentrations for EPS production were 7.07, 19.995 g/L and 23.4 g/L, respectively, with a predicted yield of 724 mg/L. The actual yield under these conditions was 708±29 mg/L which was within the 95% confidence interval. The simulated mechanistic model fit the experimental values with a high degree of correlation with R2 = 0.99, 0.96 and 0.97 for the logistic growth, substrate consumption and EPS production and degradation curves respectively. The kinetic constants μ_max = 0.29 hr-1 , Xmax = 3.44 g/L, kf = 348 mg of EPS/ g of dry biomass and kd = 0.53 hr-1 were derived from the model. The EPS administration improved the survival of irradiated mice by 50% proving it radioprotective potential and showed positive effects on structural integrity of intestinal tissue. This article is protected by copyright. All rights reserved.

Evaluation of the hypoglycemic effect of probiotics via directly consuming glucose in intestines of STZ-induced diabetic mice and glucose water-induced diabetic mice

Abstract Diabetes has steadily increased in the past few decades and causes huge influences on human health care and socioeconomic development, and drugs with minimal or no side effects for diabetes are imminent. In the present study, probiotic combination containing five selected probiotics were used to treat diabetes, the high glucose consumption capability and sound probiotic characteristics in vitro showed that the probiotics could consume all glucose within 24 h, and could tolerate low potential of hydrogen (pH) (pH = 2) and high bile salt concentration (0.3%), and they also had sound oxidation resistance [2,2-diphenyl-1-picrylhydrazyl (DPPH),∙O2−, OH, Fe2+ chelation, and the reducing powers] and antibacterial activity, highly adhere to HT-29 cells and markedly reduced the chance for pathogens to adhere to HT-29 cell (p