Antimicrobial activity of bacteriocin like inhibitory substance (BLIS) and lactic acid bacteria (LAB) isolated from traditional fermented buffalo milk from West Sumatra, Indonesia

Food preservation by chemical preservatives addition is not recommended in large quantities. However, lactic acid bacteria (LAB) metabolites can be used as a safe alternative. LAB can produce a type of antimicrobial peptide known as bacteriocin. One source of LAB that can be used as a bacteriocin-producing candidate is dadih, a traditional fermented buffalo milk product from West Sumatra, Indonesia. In this study, eight bacterial isolates isolated from dadih were identified using the catalase test and Gram straining and obtained 6 isolates that were taken as LAB. An antimicrobial activity test was carried out using the diffusion method on LAB liquid isolates suspension and crude bacteriocins from the six isolates. The isolates with the highest antimicrobial activity were DK8, the diameter of inhibiting zone of liquid isolates was 15.75 mm (Salmonella sp.), 14.25 mm (Escherichia coli), and 12.25 mm (Staphylococcus aureus). Meanwhile, the diameter of crude bacteriocin inhibition of DK 8 isolates was 8 mm (Salmonella sp.). 8 mm (E. coli), and 8.5 mm (S. aureus). Furthermore, 16S rRNA sequencing confirmed DK8 as Lactobacillus pentosus.

Whole-Genome Sequencing, Phylogenetic and Genomic Analysis of Lactiplantibacillus pentosus L33, a Potential Probiotic Strain Isolated From Fermented Sausages

Lactobacillus is a diverse genus that includes species of industrial and biomedical interest. Lactiplantibacillus pentosus, formerly known as Lactobacillus pentosus, is a recently reclassified species, that contains strains isolated from diverse environmental niches, ranging from fermented products to mammalian gut microbiota. Importantly, several L. pentosus strains present health-promoting properties, such as immunomodulatory and antiproliferative activities, and are regarded as potential probiotic strains. In this study, we present the draft genome sequence of the potential probiotic strain L. pentosus L33, originally isolated from fermented sausages. Comprehensive bioinformatic analysis and whole-genome annotation were performed to highlight the genetic loci involved in host-microbe interactions and the probiotic phenotype. Consequently, we found that this strain codes for bile salt hydrolases, adhesins and moonlighting proteins, and for Class IIb bacteriocin peptides lacking the GxxxG and GxxxG-like motifs, crucial for their inhibitory activity. Its adhesion ability was also validated in vitro, on human cancer cells. Furthermore, L. pentosus L33 contains an exopolysaccharide (EPS) biosynthesis cluster, and it does not carry transferable antibiotic resistance genes. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway and CAZymes analyses showed that L. pentosus L33 possesses biosynthetic pathways for seven amino acids, while it can degrade a wide array of carbohydrates. In parallel, Clusters of Orthologous Groups (COGs) and KEGG profiles of L. pentosus L33 are similar to those of 26 L. pentosus strains, as well as of two well documented L. plantarum probiotic strains. Conclusively, L. pentosus L33 exhibits good probiotic potential, although further studies are needed to elucidate the extent of its biological properties.

Safety Assessment of a New Strain of Lactobacillus pentosus (IBRC=11143) As a Candidate Probiotic

Background: It is believed that the consumption of an adequate amount of live lactic acid bacteria (as probiotic) may improve the health of the host. Many strains of lactic acid bacteria are generally considered to be safe. However, some strains have shown some adverse effects. Objectives: This study aimed to investigate the safety of a new strain of Lactobacillus pentosus (IBRC=11143) in Wistar rats Methods:In this experimental study, male and female Wistar rats (n=6) were used. A subacute toxicity study (for 28 days) was conducted by oral administration of Lactobacillus pentosus to the animals. In each sex, one group received saline, and the other two groups received the bacteria at doses of 1×108 and 1×109 Colony-Forming Units (CFU)/rat. Results: No significant alteration in the liver and kidney tissues was seen. However, in both sexes, there were significant differences in urea and creatinine levels between the control and the experimental groups. Some blood parameters (Lymphocyte, red blood cell, hematocrit, and hemoglobin) also showed significant changes in the groups that received the bacteria. Moreover, a significant increase in alkaline phosphatase level was observed in male rats. Conclusion: The results indicate that Lactobacillus pentosus (11143) is not entirely safe like other Lactobacillus strains. Therefore, the Lactobacillus pentosus (11143) strain may not be the right choice as a probiotic for human consumption.

Typical Moroccan goat Lactic Acid Bacteria and their assay as starters

The knowledge of lactic acid bacteria of raw milk and the main factors affecting their variability are particularly important issues for the control of cheese processing and the bioconservation of farm raw milk food products. The present research study concerned the isolation and identification of twenty strains of the Lactobacillus genus from goat milk originating from the Oulmes region, using the API 50 CH system. All isolates found represented five species: Lactobacillus plantarum (43.75 %), Lactobacillus brevis (37.75 %), Lactobacillus pentosus (6.25 %), Lactobacillus salivarus (6.25 %), and Lactobacillus acidophilus (6.25 %). According to biochemical activities, the majority of the strains displayed weak acidification and autolysis activities in milk. In contrast, they showed high extracellular proteolytic activity. All isolates produced exopolysaccharides and most of them could metabolize citrate. The absence of hemolytic activity may suggest the use of these isolates as adjunct starters in the food fermentation process.

A comparative account of biogenic synthesis of silver nanoparticles using in-house potential probiotics and their antimicrobial activity against challenging antibiotic resistant pathogens

The present work focusses on development of a safe, inexpensive, and more accessible source for biosynthesis of silver nanoparticles. Four different in-house probiotic isolates i.e., Lactobacillus pentosus S6, Lactobacillus plantarum F22, Lactobacillus crustorum F11 and Lactobacillus paraplantarum KM1 isolated from different food sources, were used in the current study to check their ability to synthesize silver nanoparticles. All the probiotics synthesized silver nanoparticles shows maximum Surface Plasmon Resonance (SPR) at a peak of 450 nm, which confirms the formation of silver nanoparticles. Scanning Electron Microscopy (SEM) analysis identified the shape and distribution of silver nanoparticles. Transmission Electron Microscopy (TEM) revealed the average size of synthesized nanoparticles in the range of 10-50 nm, with smallest size of 5 nm for silver nanoparticles synthesized by L. crustorum F11. Further, Fourier-transform infrared spectroscopy (FTIR) detected the presence of different functional groups responsible for reduction of silver ion to form silver nanoparticles. The antimicrobial activity of these AgNP was also found to be effective against different bacterial and fungal pathogens viz. antibiotic resistant Staphylococcus aureus, Bacillus cereus, Listeria monocytogenes , Pythium aphanidermatum , Fusarium oxysporum and Phytopthora parasitica . However, L.crustorum F11 synthesized AgNP showed maximum inhibition against all the bacterial and fungal pathogens, with highest against S. aureus (20 0.61mm) and F. oxysporum (23 ). Findings from this study provide a durable and ecofriendly method for the biosynthesis of silver nanoparticles, having strong antimicrobial activity against different multidrug resistant microorganisms.