Evaluation of probiotic potential of lactic acid bacteria isolated from traditional Malaysian fermentedBambangan(Mangifera pajang)

Safety aspects, probiotic potentials of yeast and lactobacillus isolated from fermented foods in North-Eastern India, and its anti-inflammatory activity

Lactobacillus and yeast obtained from fermented foods in North-East India were tested for safety and probiotic properties. All the lactobacilli and yeast tested negative for the catalase, indole, urease, phenylalanine, hemolysis, gelatin hydrolysis, and biogenic amine production tests, indicating that they are safe to use as probiotics in food supplements. Lactiplantibacillus plantarum KGL3A (accession no. MG722814) was capable of resisting the replicated gastric fluid (pH 2) till 2 h of exposure, whereas both KGL3A and Lacticaseibacillus rhamnosus K4E (accession no. KX950834.1) strains were able to resist pH 3 till 2 h of exposure with a reduction in overall viable cell count from 7.48 log CFU/mL to 1.09 log CFU/mL and 7.77 log CFU/mL to 0.83 log CFU/mL, respectively. In vitro gastric juice simulation conditions were tolerated by the yeast Saccharomyces cerevisiae WBS2A. The cell surface hydrophobicity (CSH) towards hydrocarbons (n-hexadecane) was seen highest in L. plantarum KGL3A (77.16± 0.84%) and Limosilactobacillus fermentum KGL4 accession no. MF951099 (72.60 ± 2.33%). The percentage auto-aggregation ranged from 8.70 to 25.53 after 2 h, which significantly increased to 10.50 to 26.94 during the fifth hour for cultures. Also, a higher percentage of co-aggregation was found for the culture L. rhamnosus K4E with S. typhi (34.18 ± 0.03%), E. coli (32.97 ± 0.02 %) and S. aureus (26.33 ± 0.06 %) and for the yeast S. cerevisiae WBS2A, a higher percentage of co-aggregation was found with Listeria monocytogenes (25.77 ± 0.22%). The antioxidant activity and proteolytic activity were found to be higher for Lactobacillus helveticus K14 and L. rhamnosus K4E. The proportion of decreased cholesterol was noticeably higher in KGL4 (29.65 ± 4.30%). β glucosidase activity was significantly higher in the L. fermentum KGL4 strain (0.359 ± 0.002), and α galactosidase activity was significantly higher in the L. rhamnosus K4E strain (0.415 ± 0.016). MTT assays suggested that KGL4 and WBS2A at a lower dose did not exhibit cytotoxicity.

In Vitro Antidiabetic, Antioxidant, and Prebiotic Activities of the Chemical Compounds Isolated from Guizotia abyssinica

India and Ethiopia employ Guizotia abyssinica (niger plant) as a source of edible vegetable oil. Previous studies have documented the niger plant's antioxidant properties and dietary benefits. Here, G. abyssinica extract was obtained and ten known bioactive components (1-10) were isolated. The antioxidant, antidiabetic, and prebiotic properties of whole extract and isolated components of niger and the plant's ability to cooperate symbiotically with probiotic strains were examined. Compound 10, myricetin-3-O-L-rhamnoside, had the highest antioxidant capacity measured in the 2,2-diphenylpicrylhydrazyl (DPPH, 4629.76 ± 6.02 µmol Trolox equivalent/g compound) and ferric-reducing antioxidant power (FRAP, 2667.62 ± 7.5 mol Trolox equivalent/g compound) assays. The lowest α-amylase and glycogen phosphorylase activities and glucose diffusion were obtained with whole G. abyssinica extracts, whereas compounds 8-10 had moderate inhibitory effects. G. abyssinica extract also induced the highest glucose absorption by yeast cells in the presence of 5 mM of glucose. Moreover, Lactobacillus plantarum and L. rhamnosus incubated with β-sitosterol 3-O-D-glucoside (compound 7) showed the highest prebiotic activity score. The levels of L-(+)-lactic acid isomer in the probiotic strains were the highest in presence of the whole extract and decreased progressively in the presence of flavonoid glycosides (compounds 8-10) and β-sitosterol 3-O-D-glucoside. The enzymatic profile of the probiotic strains was unaffected by the niger extract and compounds 7-10. The findings revealed that the biological activities of G. abyssinica extract are mediated by the compounds 1-10, and it may be considered as a promising plant for the treatment of diabetes mellitus.

Production, Characterization, and Application of Biosurfactant From Lactobacillus plantarum OG8 Isolated From Fermenting Maize (Zea Mays) Slurry

Biosurfactants have wide applications in several industries. However, high production costs and safety concerns have limited their comprehensive use. Twenty-five strains of lactic acid bacteria, isolated from fermenting maize slurry, were screened for biosurfactant production using the emulsification activity (E24) assay. The selected bacterium was identified molecularly using the 16S rRNA gene sequencing as Lactobacillus plantarum OG8. The effect of some cultural factors on biosurfactant production from the bacterium, using pineapple peel as a low-cost substrate, was investigated. The optimum yield of biosurfactant occurred at a 48 h incubation period, using glucose and peptone as carbon and nitrogen sources, respectively. The biosurfactant was characterized to possess mostly carbohydrates, followed by protein and lipid contents. Optima pH 10.0 and temperature 60 °C were the best for the biosurfactant activity. The biosurfactant exhibited antimicrobial activity against bacterial pathogens Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Klebsiella pneumoniae, at a concentration of 5.0 mg/mL. The use of pineapple peel as a low-cost substrate for biosurfactant production from Lactobacillus plantarum OG8 will serve for cost-effective production. The biosurfactantt produced exhibited promising properties such as thermostability and antimicrobial activity against food spoilage and pathogenes that could make it suitable for food processing and preservation.

Lactic Acid Bacteria Diversity and Characterization of Probiotic Candidates in Fermented Meats

Probiotics are defined as live microorganisms which confer health benefits to the host when administered in adequate amounts. Many lactic acid bacteria (LAB) strains have been classified as probiotics and fermented foods are an excellent source of such LAB. In this study, novel probiotic candidates from two fermented meats (pancetta and prosciutto) were isolated and characterized. LAB populations present in pancetta and prosciutto were evaluated and Lactiplantibacillus plantarum was found to be the dominant species. The antagonistic ability of selected isolates against LAB and non-LAB strains was investigated, in particular, the ability to produce anti-microbial compounds including organic acids and bacteriocins. Probiotic characteristics including antibiotic susceptibility, hydrophobicity and autoaggregation capacity; and ability to withstand simulated gastric juice, bile salt, phenol and NaCl were assessed. Among the characterized strains, L. plantarum 41G isolated from prosciutto was identified as the most robust probiotic candidate compared. Results from this study demonstrate that artisanal fermented meat is a rich source of novel strains with probiotic potential.

Functional Food for the Stimulation of the Immune System Against Malaria

Drug resistance has become a threat to global health, and new interventions are needed to control major infectious diseases. The composition of gut microbiota has been linked to human health and has been associated with severity of malaria. Fermented foods contribute to the community of healthy gut bacteria. Despite the studies connecting gut microbiota to the prevention of malaria transmission and severity, research on developing functional foods for the purpose of manipulating the gut microbiota for malaria control is limited. This review summarizes recent knowledge on the role of the gut microbiota in malaria prevention and treatment. This information should encourage the search for lactic acid bacteria expressing α-Gal and those that exhibit the desired immune stimulating properties for the development of functional food and probiotics for malaria control.

Screening of Host Specific Lactic Acid Bacteria Active Against Escherichia coli From Massive Sample Pools With a Combination of in vitro and ex vivo Methods

A novel three-step combination of in vitro and ex vivo screening was established to massively screen host derived lactic acid bacteria (LAB) from the broiler chicken intestine with inhibitory activity against Escherichia coli. In a first step, a massive sample pool consisting of 7102 broiler-derived colonies from intestinal contents were established and sub-cultured. Supernatants thereof were incubated with an E. coli model strain to screen suitable isolates with inhibitory activity. A total of 76 isolates of interest were subsequently further studied based on either pH dependent or -independent activity in the second step of the assay. Here, in-depth growth inhibition of the E. coli model strain and the potential of isolates for lactic acid production as inhibitory substance were indexed for all isolates. Resulting scatter plots of both parameters revealed five isolates with exceptional inhibitory activity that were further studied under ex vivo condition in the third step of the assay. These isolates were taxonomically classified as strains of the species Lactobacillus agilis, Lactobacillus salivarius, and Pediococcus acidilactici. Samples from the broiler chicken intestine were inoculated with the Lactobacillus isolates and the E. coli model strain. After 8 and 24 h incubation, respectively, growth of the E. coli model strain was monitored by cultivation of the E. coli strain in antibiotic supplemented medium. By their superior inhibitory activity against the E. coli model strain, one L. agilis and one L. salivarius strain were selected and characterized for further application as probiotics in broiler chicken. Additionally, their antibiotic resistance patterns and resilience under gastric stress of isolates were also characterized. The results of this study demonstrate that the novel isolation procedure was able to efficiently and rapidly isolate and identify bacterial strains from a massive sample pool with inhibitory potential against specific types of bacteria (here E. coli). The introduction of the final ex vivo selection step additionally confirmed the inhibitory activity of the strains under conditions simulating the intestinal tract of the host. Furthermore, this method revealed a general potential for the isolation of antagonistic strains that active against other pathogenic bacteria with specific biomarker.

Evaluation of probiotic Lactobacillus plantarum against foodborne pathogens and its fermentation potential in improving Lolium multiflorum silage quality

The objective of this study was to isolate the lactic acid bacteria from fermented silage sample and analyze their antibacterial activities, probiotic properties, and fermentation potential in silage. Eleven lactic acid bacteria (LAB) were selected based on distinct morphologies and preliminary studies. Cell-free supernatant (CFS) was then prepared from the selected strains for antibacterial analysis. L-30 strain and its CFS showed highest inhibition (> 10 mm) against tested foodborne pathogens as compared to other strains. Hereafter, the strain L-30 was named as KCC-30 and used for further studies. KCC-30 can survive in the harsh conditions of GIT such as low pH ( 2) and bile salt environment (oxgal) than standard L. plantarum KACC-91016 (pH 2: 27.2% vs 20.5%; oxgal: 72.3% vs 57.7%, both p < 0.05). In addition, KCC-30 exhibited strong auto-aggregation (68.3% vs 51.5%) and co-aggregation (33% vs 23.9%) properties. For silage experiment, KCC-30 treatment did not alter the nutrient profiles of silage. At the same time, KCC-30 treatment increased the lactic acid content of silage as compared to untreated silage (5.55 DM% vs 3.11 DM%). An increase of lactic acid content in the silage is due to higher lactic acid bacteria population in KCC-30 treated silage (15.33 × 10⁷ CFU/g vs 7.66 × 10⁷ CFU/g) than untreated silage (p < 0.05). Overall data suggested that KCC-30 exhibited strong probiotic potential and improved the quality of Lolium multiflorum silage by increasing the lactic acid level. Therefore, KCC-30 could be considered as potential strain to improve the fermentation quality of L. multiflorum silage.