Evaluation of probiotic properties of Levilactobacillus brevis isolated from hawthorn vinegar.

Probiotic microorganisms are increasing their interest today due to the benefits they provide to humans. Vinegar is the process of processing foods containing carbohydrates that can be fermented by acetic acid bacteria and yeasts. Hawthorn vinegar is also important in terms of amino acids, aromatic compounds, organic acids, vitamins and minerals it contains. Depending on the variety of microorganisms in it, the content of hawthorn vinegar changes, especially its biological activity. Bacteria were isolated from handmade hawthorn vinegar obtained in this study. After performing its genotypic characterization, it has been tested that it can grow in low pH environment, survive in artificial gastric and small intestinal fluid, survive against bile acids, surface adhesion characteristics, antibiotic susceptibility, adhesion, and degrade various cholesterol precursors. According to the results obtained, the studied isolate is Levilactobacillus brevis, it can reproduce best at pH 6.3, survives 72.22% in simulated gastric juice, 69.59% in small intestinal fluid, and 97% adhesion to HTC-116. Partially reproduces even in the presence of 2% ox-bile, surface hydrophobicity is 46.29% for n-hexadecane. It has been determined that it can degrade 4 different cholesterol precursors except for Sodium thioglycolate and is generally resistant to antibiotics except for CN30 and N30. Considering the experimental findings of Levilactobacillus brevis isolated from hawthorn vinegar for the first time, it can be said that Levilactobacillus brevis has probiotic properties.

Screening and Identification of Probiotic Lactobacilli from the Infant Gut Microbiota to Alleviate Lead Toxicity.

Lead (Pb2+) exposure cause a potential hazard to human health and the ecological environment; however, prevention and treatment of Pb2+ toxicity remain problems. The aim of this study is to isolate a novel probiotic lead (Pb2+)-resistant Lactobacillus strain from the infant gut microbiota and to determine whether they have the probiotic properties and investigate its preventive and therapeutic effects in the early-life Pb2+ exposure mouse model. In the present study, a total of 64 Pb2+-resistant colonies were isolated from the infant gut microbiota. Of these colonies, SYF-08, identified as Lacticaseibacillus casei, exhibited a Pb2+-binding capacity and Pb2+ tolerance. The in vivo study showed that SYF-08 treatment could effectively reduce Pb2+ levels in the blood, alleviate Pb2+ enrichment in bone and brain tissues, and recover the intestinal and brain damage in both dams and offspring. SYF-08 treatment also improved the antioxidant index in the liver and kidney tissues, while increasing the diversity of the intestinal microbiota of the offspring. The results of the in vitro and in vivo studies suggest that SYF-08, isolated from infant fecal samples, is a promising candidate probiotic against Pb2+ toxicity.

Isolation, characterization and comparative genomics of potentially probiotic Lactiplantibacillus plantarum strains from Indian foods.

Lactiplantibacillus plantarum is one of the most diverse species of lactic acid bacteria found in various habitats. The aim of this work was to perform preliminary phenotypic and genomic characterization of two novel and potentially probiotic L. plantarum strains isolated from Indian foods, viz., dhokla batter and jaggery. Both the strains were bile and acid tolerant, utilized various sugars, adhered to intestinal epithelial cells, produced exopolysaccharides and folate, were susceptible for tetracycline, erythromycin, and chloramphenicol, did not cause hemolysis, and exhibited antimicrobial and plant phenolics metabolizing activities. The genetic determinants of bile tolerance, cell-adhesion, bacteriocins production, riboflavin and folate biosynthesis, plant polyphenols utilization, and exopolysaccharide production were found in both the strains. One of the strains contained a large number of unique genes while the other had a simultaneous presence of glucansucrase and fructansucrase genes which is a rare trait in L. plantarum. Comparative genome analysis of 149 L. plantarum strains highlighted high variation in the cell-adhesion and sugar metabolism genes while the genomic regions for some other properties were relatively conserved. This work highlights the unique properties of our strains along with the probiotic and technically important genomic features of a large number of L. plantarum strains.

Deep Functional Profiling of Wild Animal Microbiomes Reveals Probiotic Bacillus pumilus Strains with a Common Biosynthetic Fingerprint.

The biodiversity of microorganisms is maintained by intricate nets of interactions between competing species. Impaired functionality of human microbiomes correlates with their reduced biodiversity originating from aseptic environmental conditions and antibiotic use. Microbiomes of wild animals are free of these selective pressures. Microbiota provides a protecting shield from invasion by pathogens in the wild, outcompeting their growth in specific ecological niches. We applied ultrahigh-throughput microfluidic technologies for functional profiling of microbiomes of wild animals, including the skin beetle, Siberian lynx, common raccoon dog, and East Siberian brown bear. Single-cell screening of the most efficient killers of the common human pathogen Staphylococcus aureus resulted in repeated isolation of Bacillus pumilus strains. While isolated strains had different phenotypes, all of them displayed a similar set of biosynthetic gene clusters (BGCs) encoding antibiotic amicoumacin, siderophore bacillibactin, and putative analogs of antimicrobials including bacilysin, surfactin, desferrioxamine, and class IId cyclical bacteriocin. Amicoumacin A (Ami) was identified as a major antibacterial metabolite of these strains mediating their antagonistic activity. Genome mining indicates that Ami BGCs with this architecture subdivide into three distinct families, characteristic of the B. pumilus, B. subtilis, and Paenibacillus species. While Ami itself displays mediocre activity against the majority of Gram-negative bacteria, isolated B. pumilus strains efficiently inhibit the growth of both Gram-positive S. aureus and Gram-negative E. coli in coculture. We believe that the expanded antagonistic activity spectrum of Ami-producing B. pumilus can be attributed to the metabolomic profile predetermined by their biosynthetic fingerprint. Ultrahigh-throughput isolation of natural probiotic strains from wild animal microbiomes, as well as their metabolic reprogramming, opens up a new avenue for pathogen control and microbiome remodeling in the food industry, agriculture, and healthcare.

Protective Effect of Probiotics Isolated from Traditional Fermented Tea Leaves (Miang) from Northern Thailand and Role of Synbiotics in Ameliorating Experimental Ulcerative Colitis in Mice.

This study aimed to investigate the protective effect of probiotics and synbiotics from traditional Thai fermented tea leaves (Miang) on dextran sulfate sodium (DSS)-induced colitis in mice, in comparison to sulfasalazine. C57BL/6 mice were treated with probiotics L. pentosus A14-6, CMY46 and synbiotics, L. pentosus A14-6 combined with XOS, and L. pentosus CMY46 combined with GOS for 21 days. Colitis was induced with 2% DSS administration for seven days during the last seven days of the experimental period. The positive group was treated with sulfasalazine. At the end of the experiment, clinical symptoms, pathohistological changes, intestinal barrier integrity, and inflammatory markers were analyzed. The probiotics and synbiotics from Miang ameliorated DSS-induced colitis by protecting body weight loss, decreasing disease activity index, restoring the colon length, and reducing pathohistological damages. Furthermore, treatment with probiotics and synbiotics improved intestinal barrier integrity, accompanied by lowing colonic and systemic inflammation. In addition, synbiotics CMY46 combined with GOS remarkedly elevated the expression of IL-10. These results suggested that synbiotics isolated from Miang had more effectiveness than sulfasalazine. Thereby, they could represent a novel potential natural agent against colonic inflammation.

Evaluation of the Anti-Aging Effects of a Probiotic Combination Isolated From Centenarians in a SAMP8 Mouse Model.

Population aging is a prominent global problem in today's society. However, there are currently no good methods to treat or prevent aging, so anti-aging research has crucial implications. In this research, we screened bacteria from centenarians, and finally selected four probiotics (Lactobacillus fermentum SX-0718, L. casei SX-1107, Bifidobacterium longum SX-1326, and B. animalis SX-0582) to form a probiotic combination. By using the senescence accelerated mouse prone 8 (SAMP8) model, the anti-aging effects of the probiotic combination were evaluated by using behavioural testing, neuroinflammation, intestinal inflammation, and intestinal microbiota. The results showed that probiotic combination improved the impaired spatial memory, motor dysfunction, and decreased exploratory behavior in aging mice. The probiotic combination inhibited Toll-like receptor 4 (TLR4)/nuclear factor kappa B (NFκB)-induced neuroinflammation and up-regulated the expression of Sirt 1 to protect hippocampal neurons. At the same time, the probiotic combination regulated the intestinal microbiota, reduced the relative abundance of Alistipes and Prevotella in SAMP8 mice, inhibited TLR4/NFκB-induced intestinal inflammation, and increased the expression of intestinal permeability related proteins zonula occludens-1 (ZO-1) and Occuldin. The anti-aging effects of the probiotic combination may be through the regulating intestinal microbiota and inhibiting TLR4/NFκB-induced inflammation. This research provides the basis and technical support for the future production and application of the probiotic combination.

Toxicological Evaluation of a Probiotic-Based Delivery System for P8 Protein as an Anti-Colorectal Cancer Drug.

PURPOSE: This study aimed to toxicological evaluate a probiotics-based delivery system for p8 protein as an anti-colorectal cancer drug. INTRODUCTION: Lactic acid bacteria (LAB) have been widely ingested for many years and are regarded as very safe. Recently, a Pediococcus pentosaceus SL4 (PP) strain that secretes the probiotic-derived anti-cancer protein P8 (PP-P8) has been developed as an anti-colorectal cancer (CRC) biologic by Cell Biotech. We initially identified a Lactobacillus rhamnosus (LR)-derived anti-cancer protein, P8, that suppresses CRC growth. We also showed that P8 penetrates specifically into CRC cells (DLD-1 cells) through endocytosis. We then confirmed the efficacy of PP-P8, showing that oral administration of this agent significantly decreased tumor mass (~42%) relative to controls in a mouse CRC xenograft model. In terms of molecular mechanism, PP-P8 induces cell-cycle arrest in G2 phase through down-regulation of Cyclin B1 and Cdk1. In this study, we performed in vivo toxicology profiling to obtain evidence that PP-P8 is safe, with the goal of receiving approval for an investigational new drug application (IND). METHODS: Based on gene therapy guidelines of the Ministry of Food and Drug Safety (MFDS) of Korea, the potential undesirable effects of PP-P8 had to be investigated in intact small rodent or marmoset models prior to first-in-human (FIH) administration. The estimated doses of PP-P8 for FIH are 1.0×1010 - 1.0×1011 CFU/person (60 kg). Therefore, to perform toxicological investigations in non-clinical animal models, we orally administered PP-P8 at doses of 3.375 × 1011, 6.75 × 1011, and 13.5×1011 CFU/kg/day; thus the maximum dose was 800-8000-fold higher than the estimated dose for FIH. RESULTS: In our animal models, we observed no adverse effects of PP-P8 on clinicopathologic findings, relative organ weight, or tissue pathology. In addition, we observed no inflammation or ulceration during pathological necropsy. CONCLUSION: These non-clinical toxicology studies could be used to furnish valuable data for the safety certification of PP-P8.

Flow cytometric analysis reveals culture condition dependent variations in phenotypic heterogeneity of Limosilactobacillus reuteri.

Optimisation of cultivation conditions in the industrial production of probiotics is crucial to reach a high-quality product with retained probiotic functionality. Flow cytometry-based descriptors of bacterial morphology may be used as markers to estimate physiological fitness during cultivation, and can be applied for online monitoring to avoid suboptimal growth. In the current study, the effects of temperature, initial pH and oxygen levels on cell growth and cell size distributions of Limosilactobacillus reuteri DSM 17938 were measured using multivariate flow cytometry. A pleomorphic behaviour was evident from the measurements of light scatter and pulse width distributions. A pattern of high growth yielding smaller cells and less heterogeneous populations could be observed. Analysis of pulse width distributions revealed significant morphological heterogeneities within the bacterial cell population under non-optimal growth conditions, and pointed towards low temperature, high initial pH, and high oxygen levels all being triggers for changes in morphology towards cell chain formation. However, cell size did not correlate to survivability after freeze-thaw or freeze-drying stress, indicating that it is not a key determinant for physical stress tolerance. The fact that L. reuteri morphology varies depending on cultivation conditions suggests that it can be used as marker for estimating physiological fitness and responses to its environment.

Activity of Lactobacillus crispatus isolated from vaginal microbiota against Mycobacterium tuberculosis.

Tuberculosis, an infectious disease, is caused by Mycobacterium tuberculosis. It remains a significant public health issue around the globe, causing about 1.8 million deaths every year. Drug-resistant M. tuberculosis, including multi-drug-resistant (MDR), extremely-drug-resistant (XDR), and totally drug-resistant (TDR) M. tuberculosis, continues to be a threat to public health. In the case of antibiotic-resistant tuberculosis, the treatment effect of conventional antibiotics is low. Side effects caused by high doses over a long period are causing severe problems. To overcome these problems, there is an urgent need to develop a new anti-tuberculosis drug that is different from the existing compound-based antibiotics. Probiotics are defined as live microorganisms conferring health benefits. They can be potential therapeutic agents in this context as the effectiveness of probiotics against different infectious diseases has been well established. Here, we report that Lactobacillus crispatus PMC201 shows a promising effect on tuberculosis isolated from vaginal fluids of healthy Korean women. Lactobacillus crispatus PMC201 reduced M. tuberculosis H37Rv under co-culture conditions in broth and reduced M. tuberculosis H37Rv and XDR M. tuberculosis in macrophages. Lactobacillus crispatus PMC201 was not toxic to a guinea pig model and did not induce dysbiosis in a human intestinal microbial ecosystem simulator. Taken together, these results indicate that L. crispatus PMC201 can be a promising alternative drug candidate in the current tuberculosis drug regime. Further study is warranted to assess the in vivo efficacy and confirm the mode of action of L. crispatus PMC201.

Parabacteroides distasonis: intriguing aerotolerant gut anaerobe with emerging antimicrobial resistance and pathogenic and probiotic roles in human health.

Parabacteroides distasonis is the type strain for the genus Parabacteroides, a group of gram-negative anaerobic bacteria that commonly colonize the gastrointestinal tract of numerous species. First isolated in the 1930s from a clinical specimen as Bacteroides distasonis, the strain was re-classified to form the new genus Parabacteroides in 2006. Currently, the genus consists of 15 species, 10 of which are listed as 'validly named' (P. acidifaciens, P. chartae, P. chinchillae, P. chongii, P. distasonis, P. faecis, P. goldsteinii, P. gordonii, P. johnsonii, and P. merdae) and 5 'not validly named' (P. bouchesdurhonensis, P. massiliensis, P. pacaensis, P. provencensis, and P. timonensis) by the List of Prokaryotic names with Standing in Nomenclature. The Parabacteroides genus has been associated with reports of both beneficial and pathogenic effects in human health. Herein, we review the literature on the history, ecology, diseases, antimicrobial resistance, and genetics of this bacterium, illustrating the effects of P. distasonis on human and animal health.

Antipathogenic and probiotic potential of Lactobacillus brevis strains newly isolated from Algerian artisanal cheeses.

From 98 Lactobacillus strains, isolated from Algerian homemade cheeses, 14 (B1-B14) were selected based on their anti-Escherichia coli and anti-Staphylococcus aureus activities. These strains were also tested towards Listeria monocytogenes 161 and Salmonella Typhimurium LT2 and further investigated for their resistance to simulated gastrointestinal digestion, cell surface properties, ability to adhere to HT-29 cells, cholesterol lowering, antioxidant activity, and technological traits. Five isolates (B9, B13, B18, B19, and B38) were active against L. monocytogenes and Salmonella. From them, three isolates, identified as Lactobacillus brevis (B9, B13, and B38) by MALDI-TOF spectrometry and 16S rDNA sequencing, exhibited high tolerance to pancreatic juice, bile salts and acidic juices, high percentages of hydrophobicity (87, 92, and 81%, respectively), auto-aggregation (61, 68, and 72%, respectively), and adherence to HT-29 cells (79, 84, and 74%, respectively), which testify on their potential of colonization of the human intestine. On the other way, the strains B9 and B13 manifested the most relevant antioxidant activity and cholesterol-lowering ability, respectively. L. brevis strains showed low acidifying and good proteolytic activities with noticeable heat tolerance. The results gathered in this study highlighted the richness of Algerian artisanal cheeses on new lactobacilli strains with an excellent probiotic potential and demonstrated that L. brevis, largely used as nonstarter in cheese manufacture, could be exploited also as a probiotic for human use.

Probiotic capability of novel lactic acid bacteria isolated from worker honey bees gut microbiota.

The study aimed to evaluate the probiotic and safety properties of lactic acid bacterial (LAB) strains isolated from the gut microbiota of honey bee Apis mellifera L., since this source remains a promising reservoir of microbial diversity. A total of five bacterial isolates were molecularly identified using 16S rRNA gene sequencing as Enterococcus faecalis-HBE1, Lactobacillus brevis-HBE2, Enterococcus faecalis-HBE3, Enterococcus faecalis-HBE4 and Lactobacillus casei-HBE5. Gut tolerance conditions (low pH and bile salt) were evaluated. Exopolysaccharides (EPS) production, hemolytic, antioxidant activity, resistance toward antibiotics and technological characteristics (starter activity, pH and proteolysis) were examined. The five isolates showed a high survival rate (>95%), under gastrointestinal tract conditions indicating excellent potential for application as probiotics. The isolates showed no hemolytic activities and good acidification rates in the range of pH 4.6-4.98 after incubation at 37°C for 24h. The isolates exhibited promising proteolytic activity as well as DPPH radical scavenging activity in the range of 16.52-59.39%. All the tested isolates had the capability to produce exopolysaccharides except Lactobacillus casei-HBE5. These results put forward that lactic acid bacterial strain isolated from honey bee workers can be considered as promising candidates for future applications as starter cultures and could constitute new potential probiotics for the production of functional dietary products promoting health benefits.

Inhibitory effect of different chicken-derived lactic acid bacteria isolates on drug resistant Salmonella SE47 isolated from eggs.

Lactic Acid Bacteria (LAB) regulate and maintain the stability of healthy microbial flora, inhibit the adhesion of pathogenic bacteria and promote the colonization of beneficial micro-organisms. The drug resistance and pathogenicity of Salmonella enteritis SE47 isolated from retail eggs were investigated. Meanwhile, Enterococcus faecalis L76 and Lactobacillus salivarius LAB35 were isolated from intestine of chicken. With SE47 as indicator bacteria, the diameters of L76 and LAB35 inhibition zones were 12 mm and 8·5 mm, respectively, by agar inhibition circle method, which indicated that both of them had inhibitory effect on Salmonella, and L76 had better antibacterial effect; two chicken-derived lactic acid bacteria isolates and Salmonella SE47 were incubated with Caco-2. The adhesion index of L76 was 17·5%, which was much higher than that of LAB35 (10·21%) and SE47 (4·89%), this experiment shows that the higher the bacteriostatic effect of potential probiotics, the stronger the adhesion ability; then Caco-2 cells were incubated with different bacteria, and the survival of Caco-2 cells was observed by flow cytometry. Compared with Salmonella SE47, the results showed that lactic acid bacteria isolates could effectively protect Caco-2 cells; finally, after different bacteria incubated Caco-2 cells, according to the cytokine detection kit, the RNA of Caco-2 cells was extracted and transcribed into cDNA, then detected by fluorescence quantitative PCR, the results showed that L76 could protect Caco-2 cells from the invasion of Salmonella SE47, with less cell membrane rupture and lower expression of MIF and TNF genes. Therefore, the lactic acid bacteria isolates can effectively inhibit the adhesion of Salmonella and protect the integrity of intestinal barrier.

Methods for Isolation and Recovery of Bifidobacteria.

Since their discovery, bifidobacteria have been considered to represent cornerstone commensal microorganisms in the host-microbiome interface at the intestinal level. Bifidobacteria have therefore enjoyed increasing scientific and commercial interest as a source of microorganisms with probiotic potential. However, since functional and probiotic traits are strictly strain-dependent, there is a constant need to isolate, cultivate, and characterize novel strains, activities that require the utilization of appropriate media, as well as robust isolation, cultivation, and preservation techniques. Besides, effective isolation of bifidobacteria from natural environments might require different manipulation and cultivation media and conditions depending on the specific characteristics of the sample material, the presence of competitive microbiota, the metabolic state in which bifidobacteria might be encountered within the sample and the particular metabolic traits of the bifidobacterial species adapted to such inhabitation.A wide array of culture media recipes have been described in the literature to routinely isolate and grow bifidobacteria under laboratory conditions. However, there is not a single and universally applicable medium for effective isolation, recovery, and cultivation of bifidobacteria, as each growth medium has its own particular advantages and limitations. Besides, the vast majority of these media formulations was not specifically formulated for these microorganisms, and thus information on bifidobacterial cultivation options is scarce while being scattered throughout literature. This chapter intends to serve as a resource summarizing the options to cultivate bifidobacteria that have been described to date, highlighting the main advantages and limitations of each of them.

Metataxonomic analysis of microbiota from Pakistani dromedary camelids milk and characterization of a newly isolated Lactobacillus fermentum strain with probiotic and bio-yogurt starter traits.

This study was undertaken to investigate the starter and probiotic potential of lactic acid bacteria isolated from dromedarian camel's milk using both culture-dependent and -independent approaches and metataxonomic analysis. Strains of lactic acid bacteria recovered were examined in vitro for tolerance to gastric acidity, bile, and lysozyme. Bile salt hydrolysis, serum cholesterol-lowering, oxalate degradation, proteolytic activity, exopolysaccharide production, and cell surface characteristics necessary for colonizing intestinal mucosa were also evaluated. A single strain of the species, Lactobacillus fermentum named NPL280, was selected through multivariate analysis as it harbored potential probiotic advantages and fulfilled safety criteria. The strain assimilated cholesterol, degraded oxalate, produced exopolysaccharides, and proved to be a proficient alternate yogurt starter with good viability in stored bio-yogurt. A sensorial analysis of the prepared bio-yogurt was also found to be exemplary. We conclude that the indigenous L. fermentum strain NPL280 has the desired traits of a starter and adjunct probiotic culture for dairy products.

Assessment of exopolysaccharides, bacteriocins and in vitro and in vivo hypocholesterolemic potential of some Egyptian Lactobacillus spp.

Lactobacilli probiotics have been suggested to reduce cholesterol with low side effects to host. Bacteriocins and exopolysaccharides (EPSs) production are two meaningful examples of functional applications of lactobacilli in the food industry. Eight Lactobacillus strains were isolated from some Egyptian fermented food and tested for their probiotic properties. Analysis of the monosaccharide composition by thin layer chromatography showed the presence of glucose, galactose and unknown sugar. The main functional groups of EPSs were elucidated by Fourier-Transform Infrared Spectroscopy. Their fermentation cultures displayed powerful antioxidant activities extending from 97.5 to 99%, 40-75% for their EPSs and free cells, respectively, and exhibited in vitro cholesterol downgrading from 48 to 82% and 72 to 91% after 48 and 120 h, respectively. Their EPSs showed good anticancer activities against carcinoma cells with low IC50 values for HCT-116, PC-3 and HepG-2 cells. To the best of our knowledge, there have been no previous reports on the potential of Lactobacillus EPSs activity against PC-3. The selected strains, L. plantarum KU985433 and L. rhamnosus KU985436 produced two different bacteriocins as detected by gel permeation chromatography with good antimicrobial activities. In vivo study demonstrated that feeding Westar rats with fermented milk exhibited greater cholesterol, LDL and blood triglyceride reduction for both strains. Whereas, HDL was increased by about 43 and 38%, respectively, and the atherogenic indices decreased.

Contributions of exopolysaccharides from lactic acid bacteria as biotechnological tools in food, pharmaceutical, and medical applications.

Exopolysaccharides (EPS) are important bioproducts produced by some genera of lactic acid bacteria. EPS are famous for their shelf-life improving properties, techno-functional enhancing abilities in food and dairy industries, besides their beneficial health effects. Furthermore, exopolysaccharides have many prospective and well-established contributions in the field of drugs and diagnostic industry. In this review, classification of EPS produced by LAB was presented. Moreover, current and potential applications of EPS in food, dairy, baking industries, cereal-based, and functional products were described. Also, some clinical and pharmaceutical applications of EPS such as intelligent drug delivery systems (microsystems and nanosystems for sustained delivery), interpenetrating polymer networks (IPNs), anticancer drug-targeting, recombinant macromolecular biopharmaceuticals, gene delivery, tissue engineering, and role of EPS in diagnostics were highlighted. Finally, future prospects concerning enhancing EPS production, minimizing costs of their production, and exploring their contribution in further applications were discussed.

Probiotic properties of lactic acid bacteria isolated from traditionally prepared dry starters of the Eastern Himalayas.

The Himalayan people prepare dry and oval to round-shaped starter cultures to ferment cereals into mild-alcoholic beverages, which contain lactic acid bacteria (LAB) as one of the essential microbiota. There is no report on probiotic characters of LAB isolated from dry starters. Hence, we screened the probiotic and some functional properties of 37 LAB strains isolated from dry starters of the Eastern Himalayas viz. marcha, phab, paa, pee and phut. About 38% of the LAB strains showed high survival rate (> 50%) at pH 3 and 0.3% bile salts. Enterococcus durans BPB21 and SMB7 showed the highest hydrophobicity percentage of 98%. E. durans DMB4 and SMB7 showed maximum cholesterol assimilation activity. About 65% of the LAB strains showed the ability to produce ß galactosidase. Majority of the strains showed phytase activity, whereas none of the strain showed amylase activity. About 86% of LAB strains showed an optimum tolerance of 10% ethanol concentration. Genetic screening of some probiotic and functional marker genes have also been analysed. The occurrence of clp L gene, agu A gene (survival of gastrointestinal tract conditions), apf, mub1 and map A gene (adhesion genes) was higher compared to other genes. The occurrence of bsh gene (bile salt tolerance) was detected in Pediococcus pentosaceus SMB13-1 and Enterococcus faecium BPB11. Gene ped B for pediocin with amplicon size of 375 bp was detected in E. durans DMB13 and Pediococcus acidilactici AKB3. Detection of nutritional marker gene rib A and fol P in some strains showed the potential ability to synthesize riboflavin and folic acid. LAB with probiotic and functional properties may be explored for food industry in future.

Biopreservation and probiotic potential of a large set of lactic acid bacteria isolated from Brazilian artisanal cheeses: From screening to in product approach.

The increasing interest in products with functional properties has encouraged the search for new lactic acid bacteria (LAB) present in natural sources, as traditional fermented foods. In this study, a large set of wild LAB isolates (n = 220) from Brazilian artisanal cheeses (BAC) were assessed for their probiotic and biopreservation potential. First, the rational selection was performed. From the tested isolates, 92 (41.8 %) were resistant to low pH (2 and 3). These isolates were submitted to bile salt (0.4 % Oxgall powder) resistance, and 22 were selected and submitted to adhesion assays. The autoaggregation values ranged from 68.5-99% and were considered moderate to high (20-70 %). Hydrophobicity values varied significantly between LAB (5.0-64.3%), and seven isolates presented values higher than 40 %. All selected LAB (n=22) were capable of adhering to Caco-2 (> 70 %) cells, and none isolate displayed any tested gene for biogenic amine production. Most isolates (18/22) showed less than 1 log CFU reduction after passage through the simulated gastrointestinal tract (GIT) conditions. A total of twenty isolates satisfied key in vitro criteria to be considered as probiotics. A hierarchical cluster analysis (HCA) was performed, and two clusters were observed, showing high variability between Lactobacillus plantarum isolates regarding adhesion properties and survival to GIT stress and one influence of the source of isolation on these properties. After screening, the antimicrobial activity of Lb. plantarum (1QB77) was tested in microcheeses in which survival of two relevant pathogenic bacteria (Staphylococcus aureus and Listeria monocytogenes) was monitored along ripening and after a simulated GIT passage, concomitantly. L. plantarum (1QB77) has shown the ability to reach high counts (∼ 9 log CFU/g) at the end of ripening. This isolate was also able to reduce counts of S. aureus and L. monocytogenes in microcheeses in approx. 2.3 and 2.5 log CFU/g, respectively, until the 21st day of ripening; and about 3.2 and 3.5 log CFU/g after simulated GIT passage. Overall, the assessment of the probiotic properties of a large set of LAB was fundamental for gaining insights on the technological, functional, and potential regional traits of wild LAB isolates that can be used to develop starter cultures for tailored applications.

Identification and in vitro evaluation of probiotic attributes of lactic acid bacteria isolated from fermented food sources.

Consumer's vigilance towards health-promoting foods beyond only taste and nutrition has increased the recognition for probiotic products. In the present study, various parameters have been studied to define the probiotic properties of cultures isolated from different fermented products. Around 118 samples were selectively screened for antimicrobial compound (AMC) producing isolates by overlay-plate assay using Micrococcus luteus ATCC9341. Among 134 zone producing isolates, 48 cultures showing Gram-positive, catalase negative, non-spore forming and non-motile rods and cocci were selected. Subsequently, 18 strains were chosen based on non-hemolytic, absence of biogenic amine production, gelatinase and lecithinase negative trait for safer isolates. These were identified by biochemical assays and then subjected to RAPD-PCR. The selected cultures DB-1aa, DB-b2-15b, Cu2-PM7, Cu3-PM8 and IB-pM15 were identified by 16S rDNA sequencing as Enterococcus durans, Enterococcus faecium, Lactobacillus plantarum, and two Lactobacillus fermentum, respectively. Several in vitro experiments were carried out including acid and bile tolerance, survival under simulated gastrointestinal condition, adhesion assay to evaluate the probiotic potential of the isolates. In addition, the isolates were studied for competent properties such as antibacterial, antioxidant activity, and enzyme production for their functional application. The results of the study prove the efficiency of selected isolates as potential probiotic cultures and hence can be recommended for application in any functional food formulations.