Evaluation of probiotic properties of lactic acid bacteria (LAB) strain GXMU-G1 against Vibrio parahaemolyticus and isolation and purification of its bacteriocin.

Sumatran Orangutan (Pongo abelii) and Long-tailed Macaque (Macaca fascicularis) population are both facing a decline in the wild. Despite of the well-known cause of decline, which is habitat degradation, several issues like disease and infection are common in ex-situ conservation site. The study aimed to evaluate antimicrobial properties of lactic acid bacteria (LAB) isolated from faeces of Pongo abelli and Macaca fascicularis, as potential antagonist against common gut pathogens based on in vitro study. Following parameters were examined such as: antagonistic activity against Salmonella typhii, Escherichia coli, and Shigella sp. using disk-diffusion method; acid and bile-salt tolerance using simulated gastrointestinal fluids (SIF) and co-aggregation ability. The study obtained ten isolates in which six of them exhibited antagonist properties namely isolate OU1, OU2, OU5, MEP1, MEP3 and MEP5. Two isolates, namely OU5 and MEP5 showed good results in terms of acid and bile-salt tolerance and co-aggregation ability. The results then may imply the promising use of potential LAB as probiotics in the future study.

The aim of the present study was to assess the technological and safety potential of 207 lactic acid bacteria (LAB) and 195 yeast strains isolated from spontaneously fermented Greek wheat sourdoughs. More accurately, the amylolytic, proteolytic, lipolytic, phytase and amino acid decarboxylase activities, along with the production of exopolysaccharides and antimicrobial compounds by the LAB and yeast isolates, were assessed. A well diffusion assay revealed seven proteolytic LAB and eight yeast strains; hydrolysis of tributyrin was evident only in 11 LAB strains. A further Sodium Dodecyl Sulphate-Polyacrylamide Gel Electrophoresis (SDS-PAGE) indicated partial hydrolysis of gluten. Lipolysis kinetics over 21 days was applied, exhibiting that lipolytic activity ranged from 6.25 to 65.50 AU/mL. Thirteen LAB inhibited Penicillium olsonii and Aspergillus niger growth and 12 yeast strains inhibited Pe. chrysogenum growth. Twenty-one Lactiplantibacillus plantarum strains exhibited inhibitory activity against Listeria monocytogenes, as well as several sourdough-associated isolates. The structural gene encoding plantaricin 423 was detected in 19 Lcb. plantarum strains, while the structural genes encoding plantaricins NC8, PlnE/F, PlnJ/K, and S were detected in two Lcb. plantarum strains. None of the microbial strains tested exhibited exopolysaccharide (EPS) production, amino acid decarboxylase, amylolytic or phytase activity. The technological and safety potential of the Lcb. plantarum and Wickerhamomyces anomalus strains was highlighted, since some of them exhibited proteolytic, lipolytic, antibacterial and antimould activities.

This study evaluated the functional properties of lactic acid bacteria (LAB) isolated from Vietnamese feces under various heat-treatment conditions by assessing their antioxidant activity, lipoteichoic acid (LTA) content, and immunomodulatory effects. Among the six LAB strains isolated, four (<i>Ligilactobacillus salivarius</i> V4, <i>Limosilactobacillus fermentum</i> V8, <i>Lactiplantibacillus plantarum</i> V10, and V11) were selected based on their acid and bile resistance, proteolytic activity, and <i>β</i>-galactosidase activity. Heat treatment (65°C for 60 min or 95°C for 10 min) completely inactivated LAB, reducing protein and phosphate content as treatment intensity increased. Antioxidant assays [2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), 2,2-diphenyl-1-picrylhydrazyl, and ferric reducing antioxidant power] revealed comparable or superior activity in heat-treated (HT) cells compared to live cells, with <i>L. plantarum</i> V10 showing the highest activity. LTA content analysis of HT <i>L. plantarum</i> V10 showed the highest LTA content (1,244 ppm) at 65°C for 60 min, surpassing that of the commercial dead cell <i>Enterococcus faecalis</i> EF-2001. Anti-inflammatory activity tests indicated no cytotoxicity at concentrations below 10⁷ CFU/mL, and HT cells treated at 65°C for 60 min showed the highest inhibition of nitric oxide and the lowest expression levels of inflammatory cytokines [tumor necrosis factor-<i>α</i>, interleukin (IL)-1<i>β</i>, IL-6]. Consequently, 65°C for 60 min was established as the optimal heat-treatment condition. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis following digestive enzyme treatment revealed that HT <i>L. plantarum</i> V10 was not degraded by amylase or pepsin, but was partially degraded by oxgall. These findings suggest that HT <i>L. plantarum</i> V10 is a promising functional ingredient with antioxidant and immunoregulatory properties and is especially suitable for the Southeast Asian market.

We report the evaluation of probiotic properties of potent lactic acid bacteria (LAB) from the gut of freshwater fishes, Labeo rohita and Catla catla, for eventually developing probiotic strains for the prevention of bacterial infections in aquaculture and food preservation. Five different LAB strains were isolated and characterized for their probiotic properties. Based on physiological, morphological and biochemical characteristics, three isolates from Labeo rohita and two from Catla catla were identified as putative probiotics and were denoted as LR11, LR14 and LR16 and CC3 and CC4, respectively. Isolates CC3 and CC4 were acid (pH 2.5) and bile salt (0.3% oxygall) tolerant and exhibited strong antibacterial activities against all pathogens including Aeromonas hydrophila. In addition, all LAB isolates were susceptible to tested antibiotics, except CC3 and CC4 which were vancomycin resistant. Furthermore, the isolates CC3 and CC4 showed significantly higher in vitro cell surface properties, i.e., hydrophobicity, auto- and co-aggregation. Biochemical tests, PCR detection and 16S rRNA sequence analysis established that LR11, LR14, LR16, CC3 and CC4 are Enterococcus avium TSU11, Enterococcus pseudoavium TSU14, Enterococcus raffinosus TSU16, Lactobacillus gasseri TSU3 and Lactobacillus animalis TSU4, respectively. Studies revealed that, Lactobacillus gasseri TSU3 and Lactobacillus animalis TSU4 are ideal probiotic candidates for its use in aquaculture and require further exploratory in vivo evaluation and safety studies.

BackgroundIndigenous communities residing in the Darjeeling Himalayan region and its adjacent hilly areas have a deeply rooted cultural tradition of consuming a diverse range of vegetable and milk-based fermented products, believed to confer various health advantages. With this traditional knowledge, lactic acid bacteria (LAB) were isolated from popular fermented foods such as Chhurpi (derived from Bos grunniens milk), Gundruk (made from Brassica juncea leaves), Sinki (derived from Raphanus sativus taproots), and Kinema (produced from Glycine max beans). This study aimed to investigate the probiotic properties of the prevalent LABs, including aggregation properties, bile salt hydrolase activities, survival under gastro-inhibitory conditions, safety evaluations, and their potential health-promoting attributes, with a specific focus on inhibiting α-amylase and α-glucosidase enzymes.ResultsFive of the LAB isolates demonstrated notable viability rates exceeding 85% when exposed to gastro-inhibitory challenges. Based on 16S rRNA gene sequencing, these isolates were identified as Pediococcus pentosaceus (isolate GAD), Lactobacillus plantarum (isolates KAD and CAD), Lactobacillus brevis (isolate SAD), and Lactiplantibacillus plantarum (isolate CMD). These LAB isolates exhibited versatile carbon source utilization, significant auto- and co-aggregation, and bile salt hydrolase (BSH) properties. Auto-aggregation capacity notably increased over time, ranging from 30 to 150 min, with percentage increments from 4.83 ± 1.92% to 67.60 ± 5.93%. L. brevis SAD displayed the highest co-aggregation increment (%) against Staphylococcus aureus, while L. plantarum KAD demonstrated potent antimicrobial activity. In vitro analyses postulated potential health benefits related to antidiabetic properties, particularly inhibiting α-amylase and α-glucosidase enzymes. L. brevis SAD exhibited the highest α-glucosidase inhibitory activity, while L. plantarum KAD displayed the most potent α-amylase inhibitory activity. Comprehensive safety assessments, including antibiotic susceptibility profiling, hemolytic activity evaluation, and in vivo acute toxicity studies, confirmed the suitability of these LAB isolates for human consumption.ConclusionsThe isolates show promising probiotic characteristics and significant potential in addressing metabolic health. These results carry substantial scientific implications, suggesting the pharmaceutical-based applications of these traditional fermented foods. Further in vivo investigation is recommended to fully elucidate and exploit the health benefits of these LAB isolates, opening avenues for potential therapeutic interventions and the development of functional foods.

Probiotic potential and amylolytic properties of lactic acid bacteria isolated from Chinese fermented cereal foods

Metabolic and Functional Properties of Lactic Acid Bacteria in the Gastro-intestinal Ecosystem: A comparative in vitro Studybetween Bacteria of Intestinal and Fermented Food Origin

Fermented milk products are a major source of health-promoting microorganisms known as probiotics. To characterize the probiotic properties of lactic acid bacteria isolated from Ghanaian traditionally fermented milk, thirty (30) isolates comprising Enterococcus faecium (1), Lactobacillus fermentum (14), Lb. plantarum (2) and Pediococcus acidilactici (13) identified by 16S rRNA gene sequencing, were tested for survival at low pH (2.5) and bile salts (0.3% (w/v)), hydrophobicity, co-aggregation, auto-aggregation and antimicrobial activities against selected pathogens. Safety of potential probiotic bacteria was assessed by hemolytic activity on blood agar and susceptibility to nine different antibiotics. Majority (90%) of the strains showed survival rates above 80% at pH (2.5) and in bile salts (0.3% (w/v)). Hydrophobicity ranged from 5 to 61% while cell auto-aggregation ranged from 41 to 80% after 24h. Co-aggregation with E. coli (3.7-43.9%) and S. Typhimurium (1.3-49.5%) were similar for the LAB strains at 24h. Cell- free supernatants of all LAB strains inhibited E. coli while S. Typhimurium was not sensitive to cell-free supernatants of five Pd. acidilactici strains: OS24h20, OS18h3, OY9h19, OS9h8 and 24NL38. None of the LAB strains showed β-hemolysis but 38% of strains showed α-hemolysis. Susceptibilities to antibiotics were strain-specific; only four strains, two Lb. fermentum and two Pd. acidilactici were susceptible to all nine antibiotics tested. Based on high survival rates in bile salts, low pH and generally good hydrophobicity, auto-aggregation, co-aggregation and inhibitory activities, 15 out of 30 strains tested were considered qualified candidates for development of probiotic cultures for fermented milk products in sub-Saharan Africa.

Interaction between probiotic lactic acid bacteria and canine enteric pathogens: a risk factor for intestinal Enterococcus faecium colonization?

In poultry farming, antibiotics have been widely utilized as growth enhancers to promote intestinal health and reduce mortality in livestock from pathogenic microorganisms. Many countries have implemented bans on the excessive use of antibiotics because of increasing concerns regarding the resistance of bacteria to antibiotics and the presence of antibiotic residues in poultry products. To counteract this problem, probiotics could be used as adjuncts or as substitutes for preserving a diverse and balanced microflora to prevent the colonization and multiplication of pathogenic bacteria in the gastrointestinal (GI) tract, while also improving poultry performance. The functional properties of lactic acid bacteria (LAB) and their potential as poultry probiotics have been extensively recorded. Hence, this study aimed to assess the potential probiotic properties of LAB for the development of poultry probiotics by isolating lactic acid bacteria from the digestive tracts of broiler chickens. To achieve this aim, a total of 66 LAB isolates were isolated from the crops and small intestines of broiler chickens, which were screened and evaluated for their probiotic properties, among which 11 strains exhibited excellent probiotic traits and were identified by 16S rDNA sequencing as Enterococcus faecalis strain ATCC 19433 (isolates C4 and C5), Pediococcus pentosaceus strain DSM 20336 (isolates C7, C13 C24, SI23 and SI38), Streptococcus salivarius strain ATCC 7073 (isolate SI4) and Levilactobacillus brevis ATCC 14869 (isolates SI6, SI8 and SI9). The selected strains inhibited tested pathogenic bacterial growth Listeria monocytogenes (ATCC 7644), Salmonella enterica (ATCC 13314), Pseudomonas aeruginosa (ATCC 27853) and Staphylococcus aureus (ATCC 29213) with zones of inhibition ranging from 9.00 ±5.66 to 30.00 ±0 mm and survived in simulated gastric juice with a cell viability count greater than 7.0 CFU/ml. Furthermore, the isolates demonstrated remarkable auto aggregation and coaggregation capabilities, along with α-glucosidase inhibitory activity ranging from 25.84 ± 3.08% to 61.77 ± 6.16%. Principal component analysis results indicated that L. brevis NKFS9, P. pentosaceus NKFS3, P. pentosaceus NKFS11 and E. faecalis NKFS1 are the most promising LAB candidates that can be utilized for the development of a multi probiotic strain for broiler chickens. In conclusion, the lactic acid bacteria (LAB) strains isolated from the crops and small intestines of broiler chickens present a valuable prospect for the development of effective probiotics. These probiotics can be utilized as a supplementary inclusion in poultry feed, reducing or obviating the need for antibiotics as growth promoters. Nevertheless, additional in vivo studies are essential to closely monitor and assess the beneficial effects of probiotics on the GI tract of chickens.

Objective : Fermentation is an important step in the post-harvest processing of cocoa beans. The quality of beans and chocolate depends strongly on the type and characteristics of microbial strains involved in the fermentation. This study investigates some functional properties of lactic acid bacteria (LAB), involved in Cote d’Ivoire cocoa fermentation. Methodology and results : Bacterial growth was monitored during spontaneous heap fermentation using plate count and decimal dilution methods. LAB was present throughout the fermentative process with a load comprised between 6.0 log (UFC/g of bean) at the beginning to 6.60 log (UFC/g of bean) at the end. The maximum load of LAB corresponding to 7.22 log (UFC/g of bean) was reached after 24 h of fermentation in the condition of 42 °C of temperature and pH round 3.55. Among the 150 strains isolated, 99 were lactobacilli and 51 lactococci. Almost all these LAB showed ability to ferment glucose, fructose and sucrose with an important acidification capacity while only 8 strains belonging to lactococci proved to be able to assimilate citrate. Moreover, a weak proportion (7.33 %) of LAB strains isolated was heterofermentative type. These heterofermentative LAB strains were particularly characterized by a great fermentative capacity especially with glucose and sucrose with a gas production up to 5 mL. Conclusion and application of results : The citrate metabolism and the strong fermentative capacity of certain LAB strains, indicate interesting technological traits potentially useful for their utilization as starters in cocoa fermentation. Keywords : lactic acid bacteria; fermentative power; cacao fermentation; acidification; citrate metabolism.

Objective: Fermentation is an important step in the post-harvest processing of cocoa beans. The quality of beans and chocolate depends strongly on the type and characteristics of microbial strains involved in the fermentation. This study investigates some functional properties of lactic acid bacteria (LAB), involved in Côte d'Ivoire cocoa fermentation. Methodology and results: Bacterial growth was monitored during spontaneous heap fermentation using plate count and decimal dilution methods. LAB was present throughout the fermentative process with a load comprised between 6.0 log (UFC/g of bean) at the beginning to 6.60 log (UFC/g of bean) at the end. The maximum load of LAB corresponding to 7.22 log (UFC/g of bean) was reached after 24 h of fermentation in the condition of 42 °C of temperature and pH round 3.55. Among the 150 strains isolated, 99 were lactobacilli and 51 lactococci. Almost all these LAB showed ability to ferment glucose, fructose and sucrose with an important acidification capacity while only 8 strains belonging to lactococci proved to be able to assimilate citrate. Moreover, a weak proportion (7.33 %) of LAB strains isolated was heterofermentative type. These heterofermentative LAB strains were particularly characterized by a great fermentative capacity especially with glucose and sucrose with a gas production up to 5 mL. Conclusion and application of results: The citrate metabolism and the strong fermentative capacity of certain LAB strains, indicate interesting technological traits potentially useful for their utilization as starters in cocoa fermentation.Keywords: lactic acid bacteria; fermentative power; cacao fermentation; acidification; citrate metabolism.

Evaluation of regulatory capacity of three lactic acid bacteria on the growth performance, non-specific immunity, and intestinal microbiota of the sea cucumber Apostichopus japonicus

The use of microorganisms as beneficial crops for human and animal health has been studied for decades, and these microorganisms have been in practical use for quite some time. Nowadays, in addition to well-known examples of beneficial properties of lactic acid bacteria, bifidobacteria, selected Bacillus spp., and yeasts, there are several other bacteria considered next-generation probiotics that have been proposed to improve host health. Aquaculture is a rapidly growing area that provides sustainable proteins for consumption by humans and other animals. Thus, there is a need to develop new technologies for the production practices associated with cleaner and environment-friendly approaches. It is a well-known fact that proper selection of the optimal probiotics for use in aquaculture is an essential step to ensure effectiveness and safety. In this critical review, we discuss the evaluation of host-specific probiotics in aquaculture, challenges in using probiotics in aquaculture, methods to improve the survival of probiotics under different environmental conditions, technological approach to improving storage, and delivery along with possible negative consequences of using probiotics in aquaculture. A critical analysis of the identified challenges for the use of beneficial microbes in aquaculture will help in sustainable aquafarming, leading to improved agricultural practices with a clear aim to increase protein production.

We evaluated whether the water dispersibility of lactic acid bacteria (Enterococcus faecalis KH2) affects their efficacy. When cultured lactic acid bacteria are washed, heat-killed, and powdered, adhesion occurs between results in aggregation (non-treated lactic acid bacteria, n-LAB). However, dispersed lactic acid bacteria (d-LAB) with a lower number of aggregates can be prepared by treating them with a high-pressure homogenizer and adding an excipient during powdering. Mice were administered n-LAB or d-LAB Peyer’s patches in the small intestine were observed. Following n-LAB administration, a high amount of aggregated bacteria drifting in the intestinal mucosa was observed; meanwhile, d-LAB reached the Peyer’s patches and was absorbed into them. Evaluation in a mouse influenza virus infection model showed that d-LAB was more effective than n-LAB in the influenza yield of bronchoalveolar lavage fluids on day 3 post-infection and neutralizing antibody titers of sera and influenza virus-specific immunoglobulin A in the feces on day 14 post-infection. Therefore, the physical properties of lactic acid bacteria affect their efficacy; controlling their water dispersibility can improve their effectiveness.