Probiotic Characteristics Research Articles

Probiotic characterisation of lactic acid bacteria isolated from pickles and their potential application as presumptive probiotic starter culture in cucumber pickles

Abstract This study aimed to isolate lactic acid bacteria (LAB) from traditional pickles, analyse their probiotic properties, identify them and evaluate their potential use in the production of cucumber pickles. The majority of the isolates (65) demonstrated survival at pH 3.0, while only three isolates exhibited this ability at pH 2.0. All isolates were resistant to 0.3% and 1% bile salts and survived at 1.5% (v/v) NaCl. However, the majority of isolates exhibited survival at 10% (v/v) NaCl (73 isolates), phenol (0.4%) (64 isolates), and pepsin (81 isolates) and pancreatin presence (78 isolates). The majority of the isolates demonstrated susceptibility to antibiotics and exhibited antimicrobial activities. Furthermore, some isolates demonstrated limited proteolytic and β-galactosidase activities, with the limited proteolytic activity being particularly beneficial for contributing to positive sensorial properties in this study. Following the evaluation of the probiotic test results, selected isolates were identified as Lactiplantibacillus plantarum, Lactiplantibacillus pentosus, Levilactobacillus brevis, Lentilactobacillus parabuchneri and Pediococcus parvulus based on 16S rRNA sequence analysis. Cucumber pickles were then produced with presumptive probiotics (L. brevis T7, L. parabuchneri T10, L. plantarum T12, and P. parvulus T13) in both single and mixed cell forms, fermented for 15 days and stored at 4 °C for 5 weeks. The results demonstrated that cucumber pickles contained > 6 log CFU/g of presumptive probiotics at the end of fermentation. Sensory analysis results showed that cucumber pickles enriched with presumptive probiotics were acceptable compared to the negative control sample (spontaneously fermented). The findings also highlight the functional potential of the samples, with PS3 offering benefits for lactose-intolerant individuals and PS2 demonstrating antimicrobial activity. It is possible to offer cucumber pickles to consumers as an alternative probiotic product; however, further research is required to ascertain the viability of probiotics over an extended period.

Probiotic Characterization of Lactic Acid Bacteria from Donkey Feces in China

Probiotics are beneficial to humans and animals and often used for regulating immunity, intestinal microbiota balance, and animal growth performance. Donkey husbandry has boomed in China in recent years and there is an urgent need for probiotics effective for improving donkey health. However, studies on potential probiotic strains isolated from donkeys are scarce. This project aimed to screen LAB strains from donkey feces, detect their antimicrobial activity and evaluate their probiotic characteristics in vitro. Thirteen LAB isolates showed different degrees of antimicrobial activity against four indicator bacteria: three common pathogens (Escherichia coli, Staphylococcus aureus, and Salmonella typhimurium) and one pathogen restricted to equines (Salmonella. abortus equi), eight of which could inhibit all four pathogens. Seven isolates showed higher tolerance to low pH and bile salts, with >50% and >60% survival rates, respectively. Five of them had more than 50% survival rate to artificial gastric and intestinal fluids. Only three isolates possessed good properties, with >40% auto-aggregation, >40% hydrophobicity, and high co-aggregation with the indicator pathogens. An L9 isolate, identified as Ligilactobacillus salivarius, was sensitive to most antibiotics tested. Overall, these results indicate that the L. salivarius L9 isolate meets the requirements of the probiotics selection criteria in vitro and can potentially be developed as a probiotic for donkeys.

Isolation of New Strains of Lactic Acid Bacteria from the Vaginal Microbiome of Postmenopausal Women and their Probiotic Characteristics

Lactic acid bacteria (LAB), traditionally consumed as fermented foods, are now being applied to the medical field beyond health-functional food as probiotics. Therefore, it is necessary to continuously discover and evaluate new strains with suitable probiotic characteristics, mainly focusing on safety. In this study, we isolated eight new strains from postmenopausal vaginal fluid using culturomics approaches, an emerging area of interest. Data showed that most strains possessed significant cell surface hydrophobicity (≥ 76%), auto-aggregation capacity (17 to 61%), strong adhesion activity (8 to 34%), and excellent resistance to gastric acid, bile salt, and digestive enzyme, enhancing their survival in the gastrointestinal tract. Moreover, the strains exhibited functional characteristics, including substantial antibacterial activity with a minimal inhibitory concentration (MIC) ranging from 12.5 to 50%. They also harbored bacteriocins genes, produced short-chain fatty acids (acetate and propionate), exhibited significant phagocytic activity, possessed high antioxidative properties, rapidly depleted sodium nitrite, and exhibited proteolysis and β-glucosidase activity. In addition, heat-killed LAB strains significantly reduced the gene expressions of proinflammatory cytokines such as IL-β, IL-6, and iNOS in macrophages. Safety assessment revealed no cytotoxicity in macrophage cell lines. All strains tested negative for biogenic amine or H2O2 production, displayed no gelatinase or hemolytic activity, lacked virulence genes or detrimental enzymes, and displayed antibiotic susceptibility. In summary, these newly isolated strains demonstrate excellent probiotic functionality with a strong focus on safety, making them promising candidates for future drug development in the relevant fields.

Phylogenetic characterization of Bifidobacterium kimbladii sp. nov., a novel species from the honey stomach of the honeybee Apis mellifera.

Six novel Bifidobacterium strains H1HS16NT, Bin2N, Hma3N, H6bp22N, H1HS10N, and H6bp9N, were isolated from the honey stomach of Apis mellifera. Cells are Gram-positive, non-motile, non-sporulating, facultatively anaerobic, and fructose 6-phosphate phosphoketolase-positive. Optimal growth conditions occur at 37°C in anaerobiosis in MRS medium added with 2% fructose and 0.1% L-cysteine. The 16S rRNA gene sequences analysis revealed clustering with Bifidobacterium species found in honeybees. Strains Hma3N, H6bp22N, and H1HS16NT showed significant similarity to Bifidobacterium polysaccharolyticum JCM 34588T, with an average similarity of 99.63%. In contrast, strains Bin2N, H1HS10N, and H6bp9N were closely related to Bifidobacterium apousia JCM 34587T, with an average similarity of 99.22%. Moreover, strains Hma3N and H6bp22N exhibited ANI values of 96.65% and 96.53% when compared to Bifidobacterium polysaccharolyticum JCM 34588T, while strains H1HS16NT, Bin2N, H6bp9N, and H1HS10N revealed ANI values of 94.18%, 94.33%, 94.22%, and 95.50% respectively when compared to B. apousia JCM 34587T. dDDH analysis confirmed that strains Hma3N and H6bp22N belong to B. polysaccharolyticum, whereas strains H1HS16NT, Bin2N, H6bp9N, and H1HS10N represent a novel species. The peptidoglycan of the novel species is of the A4α type (L-Lys-D-Asp). The main cellular fatty acids of the type strain H1HS16NT are C16:0, C14:0, C19:0 cyclo ω9c, and C18:1 ω9c. The DNA G+C content of the type strain is 60.8mol%. Genome analyses of the strains were also conducted to determine their biosynthesis-related gene clusters, probiotic features, and ecological distribution patterns. Phenotypic and genotypic characterization show that strain H1HS16NT is distinct from the type strains of other recognized Bifidobacterium species. Thus, Bifidobacterium kimbladii sp. nov. (H1HS16NT=DSM 115187T=CCUG 76695T) is proposed as a novel Bifidobacterium species.

Isolation of Lactobacillus rhamnosus from Human Breast Milk and Study their Susceptibility to Antibiotics

Probiotics have an assortment of implementations in various domains. Nowadays, probiotics are used as a method to prevention many disorders and treat diseases. In this study was isolated L.rhamnosus from breast milk with the intention to studying their properties as probiotics in view of important it on infant health. 24 positive samples out of 108 have been isolated and identification by using biochemical tests and molecular diagnosis using the 16S rRNA gene. This research revealed relationship between pregnant period and existence of L.rhamnosus (P-Value < 0.05). this relationship refers to the milk of mothers who have completed nine months of pregnancy had high percent of L.rhamnosus(75%) compared to mothers who delivery in seventh or eighth month of pregnancy whereas there no relationship ( P-Value > 0.05)between existence of L.rhamnosus and mother age, infant age and type of delivery. The probiotic potential was assessed by determining antibiotic susceptibility through the disc diffusion method. Among the 24 isolates, resistance was observed to vancomycin and intermediate resistance to penicillin, streptomycin and clindamycin respectively, while susceptibility was shown to ampicillin, tetracycline, chloramphenicol and gentamycin respectively. Notably, none of the isolates exhibited hemolytic activity. Based on these findings, the isolated Lactobacillus rhamnosus displayed promising probiotic characteristics, highlighting human milk as a potential source of these beneficial bacteria

Characterization of the probiotic and functional properties of Enterococcus faecalis AQ10 isolated from chicken cecum.

Lactic acid bacteria are considered the safest alternative to antibiotics and have a broad range of applications in animal husbandry. Enterococcus faecalis is a primary component of the chicken gut microbiota; it is known for its ability to regulate intestinal microbial balance and its probiotic functions. In this study, E. faecalis strain AQ10 from isolated from was the chicken cecum and used a combination of whole-genome sequencing and phenotypic analyses to investigate its probiotic properties. Whole-genome sequencing revealed that the genome length of E. faecalis AQ10 is 2.98 Mbp, with an average guanine-cytosine content of 38.12%, and includes 2832 protein-coding genes. Genome mining tools were used to identify an antimicrobial compound gene cluster. Additionally, E. faecalis AQ10 exhibited probiotic characteristics in vivo and antibacterial effects in vitro, with organic acids potentially contributing to its anti-Klebsiella pneumoniae activity. Metabolomics analyses revealed that the supernatant of E. faecalis AQ10 contained seven organic acids. In conclusion, E. faecalis AQ10 demonstrates significant probiotic potential and may be a suitable candidate for use in livestock and poultry breeding.

Isolation, Characterization, and Assessment of Probiotic Properties of Bacillus clausii Isolated from Children’s Stools in a Northern Province of Vietnam

Bacillus clausii is a widely utilized human probiotic in various commercial products; however, there has been limited research on the isolation from diverse sources and evaluation of probiotic characteristics of Bacillus clausii. For the first time in this study, Bacillus clausii strains were isolated and evaluated from stool samples obtained from healthy volunteer children in a northern province of Vietnam. The inherent biological properties of the isolated Bacillus clausii strains were specifically examined to explore their potential application as probiotics. Thirteen colonies underwent screening through morphological and biochemical analyses, along with protein Maldi Tof MS. Among these isolates, Bacillus M23 and M31 were identified. In the preliminary safety screening, both strains exhibited negative hemolytic activity. Additionally, in vitro characteristics, such as spore formation, resistance to acid and bile salts, resistance to pathogenic microorganisms, assessment of extracellular enzyme production, and antibiotic sensitivity testing were determined for these strains, falling within the observed range for other probiotic strains. The 16S rRNA gene sequencing revealed that Bacillus M31 shared 97% similarity with Bacillus clausii DSM 8716 in the Genbank database. These findings suggest that the Bacillus clausii M31 shows promise as a probiotic candidate, although further extensive in vitro/vivo studies are necessary to validate its efficacy and safety.

Beer wheat residue as a probiotic carrier: physicochemical properties via fluid bed granulation (Beer wheat residue for lactic acid bacteria encapsulation).

In recent years, consumer preference for symbiotics containing live bacteria has surged, driven by the acknowledged health benefits. Wheat residue from beer brewing, rich in dietary fiber, remains an unexplored prebiotic raw material for developing vegan probiotic powdered products. Concerns about ambient conditions, dehydration and drying affecting bacterial cell viability prompt the investigation of protective agents (maltodextrin, l-arabinose, casein, whey protein, skimmed milk) and fluidized bed granulation microencapsulation for enhancing the survival rate of Lactiplantibacillus plantarum NKUST 817. The results of the study show that wheat residue, when utilized as the carrier with 10% indigestible dextrin FB06, served as the optimal protective agent. Optimal air inlet temperature (45, 55 and 65 °C) for fluidized bed granulation was investigated along with cell survival rate and probiotic powder characteristics such as moisture, water activity, hygroscopicity, solubility, bulk density and flowability. Bacteria without protective agents showed a survival rate of only 82.63-86.96%. However, the addition of 10% indigestible dextrin FB06 significantly increased in the survival rate of bacteria (granulated at 45-65 °C) to 93.52-95.18%. The microencapsulated bacteria powder exhibited low moisture (2.38-4.36%) and water activity (0.06-0.22). Powder fluidity, indicated by Carr's index (10.87-13.62) and the Hausner ratio (1.13-1.16%), demonstrated good flowability. Furthermore, the powder remained stable for 45 days, with a viable bacteria count of 7.29 log colony-forming units g-1 and a survival rate of 88.69%. This study pioneers vegan probiotic product development at the same time as addressing processing challenges to optimize strain resilience. This research stablishes wheat residue as a suitable candidate for a probiotics carrier. © 2024 Society of Chemical Industry.

Effects of Ultrasound Application on the Improvement of Probiotic Properties and Antioxidant Activity of Kluyveromyces marxianus, Saccharomyces cerevisiae var. boulardii and Saccharomyces cerevisiae

The objective of this study was to ascertain the impact of ultrasound application on the probiotic characteristics and antioxidant activity of yeasts. In this context, the pH changes, probiotic properties and antioxidant activities of K. marxianus (Km), S. boulardii (Sb) and S. cerevisiae (Sc) were determined by ultrasound application at different durations (5, 15, 30 and 60 minutes at 24 kHz). The lowest pH values were determined for cultures of Km (ultrasound non-applied K. marxianus), Sb-30 (30 min. ultrasound applied S. boulardii) and Sc-5 (5 min. ultrasound applied S. cerevisiae) as 4.48, 5.15 and 5.26, respectively. The hydrophobicity values of the yeast strains varied between 6% and 24%, increased with ultrasound application. Although S. boulardii had the highest tolerance to low pH and bile salts, the resistance of all yeast to low pH and bile salts decreased with ultrasound application. K. marxianus had the least survival under in vitro conditions, but ultrasound application increased survival of K. marxianus strains and slightly affected the survival rate of S. boulardii and S. cerevisiae. Increasing of duration time of ultrasound application resulted higher antioxidant activity and so the highest antioxidant activity was determined for Sb-60. Finally, ultrasound application could be used for the development of hydrophobicity and antioxidant properties of yeast cultures.

Screening of lactic acid bacteria from the milk of Sahiwal cows and characterization of their probiotic potential for preventing bovine mastitis.

Antibiotic therapy has been the most popular line of treatment for the control of mastitis worldwide during the last few decades. Alternative and sustainable treatments must be developed because pathogens are becoming more resistant to antibiotics, leading to the development and spread of antimicrobial resistance (AMR). The aim of the current investigation was to isolate lactic acid bacteria (LAB) with probiotic potential that can inhibit mastitis-causing pathogens to prevent bovine mastitis. Milk samples were collected from Sahiwal cows, and a total of 150 bacteria were isolated, of which 76 were found to be catalase negative, and resistant to vancomycin. Twenty-three isolates displayed greater acid and bile tolerance, with > 90% survivability, and were molecularly characterized by 16S rRNA partial sequencing. The autoaggregation percentages for SML7 and SML41 were greater (p<0·05) 80.38±0.19% and 80.28±0.04%, respectively. SML10 (92.04±0.26 μmol/mL) had the highest (p<0.05) ferric-reducing antioxidant power (FRAP) activity, while SML20 (52.1±0.99%) had the highest 1,1 diphenyl 2 picrylhydrazyl (DPPH) scavenging activity. All the strains were nonhemolytic or nonmucinolytic. The highest antimicrobial activity was observed in several strains (SML41, SML63, SML76, and SML60) against common mastitis-causing pathogens, namely, E. coli ATCC25922, Staphylococcus aureus ATCC25923, Enterococcus faecalis NCDC114, Streptococcus agalactiae NCDC208, and Enterococcus faecium NCDC124. The coaggregation efficacy of SML20 with S. aureus was the highest (67.69±1.21%), while SML41 showed the highest (69.75±0.29%) coaggregation efficacy with E. faecalis NCDC114 and SML63 (68.078±0.26) with S. agalactiae NCDC208. Overall, seven distinct lactic acid bacterial clusters were identified by cluster analysis of the phylogenetic tree as follows: Enterococcus hirae (1), Limosilactobacillus reuteri (1), Pediococcus acidilactici (4), Weissella confusa (11), Lactobacillus helveticus (3), Limosilactobacillus balticus (2), and Lacticaseibacillus rhamnosus (1). The Lactobacillus helveticus SML41, Lactobacillus helveticus SML60, Weissella confusa SML61, Lacticaseibacillus rhamnosus SML63, Weissella confusa SML64, and Pediococcus acidilactici SML76 isolates were found to possess the most desirable characteristics of potential probiotics based on principal component analysis (PCA). Therefore, the strains chosen in the current investigation demonstrated techno-functional characteristics that rendered them appropriate for probiotic use to treat and prevent intramammary infections in dairy cattle in a sustainable manner.

Unlocking Potential Benefits on Applications of Probiotics in Inland Aquaculture Industry: A Review

ABSTRACTInland aquaculture operations are practised all over the world, contributing about 62.6% of all farmed aquatic animals. This venture is increasing worldwide and outpacing the global market demand for fish and fishery products driven by competition with other animals, over‐population and over‐exploitation of wild capture fisheries. These operations expand globally, associated with the degradation of the culture environment due to poor aquaculture management practices and algal blooms due to nutrient influxes as well as high demand of quality fish feeds of affordable price. To overcome these challenges, sustainable, healthy and environmentally friendly alternatives including probiotics application must be adopted to achieve better production, profitability and productivity as well as a resilient culture environment. In this review, information on potential applications of probiotics in aquaculture (inland aquaculture) focused on sources, safety, approved probiotics for aquaculture, characteristics of probiotics, mode of applications and its potential use on pathogenic microbes control, fish haematological parameters, growth performance and stress responses, water quality parameter, anti‐nutritional factors and feed digestibility, limitation of using probiotics in aquaculture and lastly future perspectives on the probiotics application in aquaculture industry were reviewed and compiled for future sustainable aquaculture production and productivity and environmentally friendly. The review has also highlighted all probiotics application and their approved authority for use in farmed freshwater fish (Nile tilapia Oreochromis niloticus, Catfish Clarias gariepinus, rainbow trout Oncorhynchus mykiss and common carp Cyprinus carpio) and their cultured environment worldwide. Therefore, the review has comprised all information on the potential benefits application of probiotics in an inland aquaculture for public documentation and also identifies gaps in the aquaculture industry that require further research and assessment.

Genome mining, probiotic characteristics, and in-silico safety assessment of Limosilactobacillus fermentum AV7 isolated from Avocado fruit pulp

Genome mining, probiotic characteristics, and in-silico safety assessment of Limosilactobacillus fermentum AV7 isolated from Avocado fruit pulp

Beneficial and Safety Properties of a Bacteriocinogenic and Putative Probiotic Latilactobacillus sakei subsp. sakei 2a Strain.

This work aimed to evaluate some of the probiotic features and safety of the bacteriocin-producing Latilactobacillus sakei subsp. sakei 2a. The effect of selected commercial drugs from different generic groups and antibiotics on the growth of Ltb. sakei subsp. sakei 2a was also determined. The presence of virulence factors was determined based on PCR with total DNA from Ltb. sakei subsp. sakei 2a. Good growth of Ltb. sakei subsp. sakei 2a was recorded in MRS broth supplemented with 0.2% or 0.4% oxbile or in MRS broth adjusted to a pH from 5.0-9.0. Auto-aggregation of Ltb. sakei subsp. sakei 2a was 62.59%. Different levels of co-aggregation were recorded between Ltb. sakei subsp. sakei 2a and Enterococcus faecalis ATCC19443, Ltb. sakei ATCC15521 and Listeria monocytogenes ScottA. Growth of Ltb. sakei subsp. sakei 2a was not inhibited by commercial drugs from different generic groups. The inhibitory effect on the growth of Ltb. sakei subsp. sakei 2a was recorded only in the presence of Arotin [selective serotonin reuptake inhibitor antidepressant] Minimal Inhibition Concentration (MIC) 1.0 mg/mL, Atlansil [Antiarrhythmic] MIC 0.625 mg/mL, Diclofenac potassium [non-steroidal anti-inflammatory drug (NSAID)] MIC 2.5 mg/mL and Spidufen [NSAID] MIC 15.0 mg/mL. Only two antibiotics tested in this study, Amoxil and Urotrobel, inhibited the growth of Ltb. sakei subsp. sakei 2a with a MIC of <0.5 mg/mL and 5.0 mg/mL, respectively. However, Ltb. sakei subsp. sakei 2a generated positive PCR results on the DNA level for vanA (vancomycin resistance), hyl (hyaluronidase), esp (enterococcal surface protein), ace (adhesion of collagen) and cilA (cytolisin) and a high virulence profile when examined for the presence of virulence factors. It is important to underline that cytolysis has been described as a virulence and antibacterial factor.

Isolation, identification and in vitro probiotic characterisation of yeast strains found in fermented turnip juice

Isolation, identification and in vitro probiotic characterisation of yeast strains found in fermented turnip juice

Genome assembly of a potential probiotic Bifidobacterium bifidum BB11 strain isolated from Holstein calves.

Here we report the genome sequence of Bifidobacterium bifidum BB11 strain, isolated from the Holstein bull calf's rumen samples. The strain tested positive for probiotic characteristics such as bile salt tolerance, adhesion, and acid tolerance. The genome size was 2,200,000 bp with the guanine and cytosine (G+C) content of 62.5%.

Characterization and Biological In Vitro Screening of Probiotic Yeast Strains Isolated from Algerian Fruits.

Interest in Saccharomyces and non-Saccharomyces yeasts as biotechnological agents is growing worldwide. Here, Kluyveromyces marxianus GBC2 and two Saccharomyces cerevisiae strains FBZ4 and FBK9 were isolated from pomegranate (Punica granatum) and fig (Ficus carica), respectively, and extensively characterized for their probiotic attributes and health benefits. Overall, these strains were found to be γ-hemolytic, non-cytotoxic against Caco-2 cells, and sensitive to therapeutic antifungals. In terms of probiotic characterization, the strains were able to survive at pH 2 and in 1% bile and had high hydrophobicity and self-aggregation properties, which could explain their ability to form biofilm on a polystyrene and adhere to Caco-2 cells. Adhesion rates of 23.52%, 14.05%, and 9.44% were recorded at 37 °C for K. marxianus GBC2, S. cerevisiae FBK9, and S. cerevisiae FBZ4, respectively. Furthermore, biological screening showed a cholesterol assimilation of 54.32% for K. marxianus GBC2 and almost 33% for both Saccharomyces, more than 73% α-amylase inhibition, and good antioxidant potential for all strains; however, only K. marxianus GBC2 showed antibacterial activity against Staphylococcus aureus ATCC 25923. In light of these findings, the strains could be potential candidates for the development of novel functional foods and for probiotic applications.

Targeted Screening of Lactiplantibacillus plantarum Strains Isolated from Tomatoes and Its Application in Tomato Fermented Juice.

This study explores the functional attributes of Lactiplantibacillus plantarum (L. plantarum) strains isolated from fermented tomato juice, focusing on their physiological, biochemical, and probiotic characteristics. The identified 66 gram-positive strains included 36 L. plantarum ones, which exhibited robust growth in acidic environments (pH 2.0-5.0) and utilization of various carbohydrates. Notably, seven strains outperformed a commercial strain in extreme acidic conditions. Antioxidant activity varied, with strain A24 showing the highest hydroxyl radical scavenging ability, while strains with high surface hydrophobicity had lower DPPH scavenging activity, indicating no direct correlation between these properties. Strains also showed strain-specific differences in carbohydrate utilization and antibiotic resistance, with some resistant to gentamicin and ciprofloxacin. Survival rates under simulated gastrointestinal conditions were strain-specific, with some strains demonstrating high survival rates, indicating their potential as probiotics. Furthermore, 13 strains used as fermentation starters in tomato juice significantly enhanced antioxidant activity and reduced pH and total soluble solids, indicating efficient sugar utilization and lactic acid production. These findings suggest that L. plantarum strains are well-suited for functional food fermentation and probiotic applications, with strain-specific traits offering versatility for use in acidic food products and probiotic formulations.

Probiotic and functional characterization of newly isolated Lactiplantibacillus plantarum strains from human breast milk and proliferative inhibition potential of metabolites

Four Lactiplantibacillus plantarum strains newly isolated and identified from human breast milk in Türkiye, have probiotic, functional and proliferative inhibition potential of metabolites against colon cancer cell lines were evaluated. In simulated gastric and intestinal media, all strains exhibited strong probiotic character by showing resistance, although decreasing with time and concentration. The strains were sensitive to penicillin G, rifampin and chloramphenicol and showed antibacterial effect on all pathogenic bacteria. Citric acid, malic acid, tartaric acid, pyruvic acid and fumaric acid were not detected in the strains, while the highest amount of acetic acid was detected. The quantitative-qualitative analysis and structural characterization of exopolysaccharide (EPS) was confirmed and it was determined that the strains synthesized similar amounts. Compared to standard antioxidants, the strains showed less DPPH activity and similar ABTS activity. High amounts of metabolites of the strains showed good antiproliferative effect on Caco-2, while lower amounts showed good antiproliferative effect on the HT-29 cell line. When all the data were considered, it was determined that the strains were close to each other, but the YAAS 23 strain showed slightly better properties. In conclusion, breast milk is a unique environment harboring beneficial bacteria such as L. plantarum for human health.

Based on whole genome sequencing and metabolomics analysis the safety and probiotic characteristics of Lacticaseibacillus paracasei 36 isolated from Chinese fermented vegetables

Lacticaseibacillus paracasei is a facultative anaerobic bacterium, which is classified as a Generally Recognized as Safe (GRAS) microorganism by the Food and Drug Administration (FDA). In this study, we reported the whole genome sequence of Lacticaseibacillus paracasei 36 (L. paracasei 36), which consisted of a circular chromosome and three circular plasmids, with a total length of 3,166,237 bp and an average G + C content of 46.21%. Based on genetic analyses of production of harmful metabolites, virulence factors, and antibiotic resistance, as well as in vivo safety tests conducted with L. paracasei 36, we postulated that L. paracasei 36 was safe. The stress-response genes of L. paracasei 36 indicated that it exhibited robust tolerance to the gastrointestinal tract, temperature, and osmotic pressure. Additionally, it demonstrated high capacities for colonization and adhesion, as well as notable antioxidant activity. The metabolomic results of the L. paracasei 36 fermentation supernatant demonstrated that metabolites were mainly concentrated in amino acid metabolism and biosynthesis of other secondary metabolites, and there was a notable increase in proclavaminic acid and lactic acid. In conclusion, L. paracasei 36 possessed favorable probiotic characteristics and safety, thereby establishing it as a probiotic candidate with considerable potential.

Genomic evaluation of the probiotic and pathogenic features of Enterococcus faecalis from human breast milk and comparison with the isolates from animal milk and clinical specimens.

Enterococcus faecalis is considered a probiotic, commensal lactic acid bacterium in human breast milk (HBM), but there are circulating antibiotic resistant and virulence determinants that could pose a risk in some strains. The study aimed to conduct genomic analysis of E. faecalis isolates recovered from HBM and animal milk and to evaluate their probiotic and pathogenic features through comparative genomics with isolates from clinical specimens (e.g., urine, wound, and blood). Genomic analysis of 61 isolates was performed, including E. faecalis isolates recovered from HBM in Saudi Arabia. Genome sequencing was conducted using the MiSeq system. The fewest antibiotic resistance genes (lsaA, tetM, ermB) were identified in isolates from HBM and animal milk compared to clinical isolates. Several known and unknown mutations in the gyrA and parC genes were observed in clinical isolates. However, 11 virulence genes were commonly found in more than 95% of isolates, and 13 virulence genes were consistently present in the HBM isolates. Phylogenetically, the HBM isolates from China clustered with the probiotic reference strain Symbioflor 1, but all isolates from HBM and animal milk clustered separately from the clinical reference strain V583. Subsystem functions 188 of 263 were common in all analyzed genome assemblies. Regardless of the source of isolation, genes associated with carbohydrate metabolism, fatty acid, and vitamin biosynthesis were commonly found in E. faecalis isolates. In conclusion, comparative genomic analysis can help distinguish the probiotic or pathogenic potential of E. faecalis based on genomic features.