Marine Pediococcus pentosaceus E3 Probiotic Properties, Whole-Genome Sequence Analysis, and Safety Assessment

Identification, Safety Assessment, and Antimicrobial Characteristics of Cocci Lactic Acid Bacteria Isolated from Traditional Egyptian Dairy Products

The main objective of this study is to isolate and identify lactic acid bacteria (LAB) from various Egyptian dairy products, examine their antibacterial and hemolysis potential, and ensure their safety when used as starter cultures in different dairy industries. Egyptian dairy products are often made without the use of commercial starter cultures, using raw milk and artisanal methods. The most popular traditional dairy products are Laban Rayeb and Zabady, as well as the cheese varieties of Ras, Domiati, and Karish. The microbial communities used for fermentation and the diversity of lactic acid bacteria are the most important factors that can affect the quality of these products. In order to investigate the diversity of cocci lactic acid bacteria in Egyptian dairy products, 70 samples of raw or fermented milk and cheeses were collected from traditional cheese-making factories, local markets, and farmhouses located in the Delta area of Egypt. Following this, the LAB were isolated from the samples. One hundred fifty-seven isolates of Gram-positive, catalase-negative, and cocci bacterial species were identified via rep-PCR, and some isolates were confirmed using pheS and 16S rRNA gene sequencing, as follows: Streptococcus infantarius subsp. infantarius (three isolates), Enterococcus hirae (three isolates), Enterococcus faecium (ninety-six isolates), Enterococcus faecalis (forty isolates), Enterococcus durans (six isolates), Lactococcus garvieae (one isolate), Pediococcus acidilactici (seven isolates), and Lactococcus lactis subsp. Lactis (one isolate). These findings validate that five strains have strong antibacterial activity against Escherichia coli, Salmonella typhimurium, and Listeria monocytogenes, and one hundred thirty-four strains were safe for hemolysis. The five strains were selected as protective cultures, including Pediococcus acidilactici, Lactococcus lactis subsp. lactis, E. faecalis, and E. faecium.

Genomic Insights into Pediococcus pentosaceus ENM104: A Probiotic with Potential Antimicrobial and Cholesterol-Reducing Properties

Pediococcus pentosaceus, which often occurs in fermented foods, is characterized by numerous positive effects on the human health, such as the presence of possible probiotic abilities, the reduction of cholesterol levels, satisfactory antimicrobial activity, and certain therapeutic functions. This study was conducted with the goal of describing the genomic content of Pediococcus pentosaceus ENM104, a strain known for its inhibitory effects against pathogenic bacteria and its remarkable probiotic potential, including the induction of significant reductions in cholesterol levels and the production of γ-aminobutyric acid (GABA). The P. pentosaceus ENM104 chromosome is circular. The chromosome is 1,734,928 bp with a GC content of 37.2%. P. pentosaceus also harbors a circular plasmid, pENM104, that is 71,811 bp with a GC content of 38.1%. Functional annotations identified numerous genes associated with probiotic traits, including those involved in stress adaptation (e.g., heat stress: htpX, dnaK, and dnaJ), bile tolerance (e.g., ppaC), vitamin biosynthesis (e.g., ribU, ribZ, ribF, and btuD), immunomodulation (e.g., dltA, dltC, and dltD), and bacteriocin production (e.g., pedA). Notably, genes responsible for lowering cholesterol levels (bile salt hydrolase, bsh) and GABA synthesis (glutamate/GABA antiporter, gadC) were also identified. The in vitro assay results using cell-free supernatants of P. pentosaceus ENM104 revealed antibacterial activity against carbapenem-resistant bacteria, such as Pseudomonas aeruginosa, Klebsiella pneumoniae, and Acinetobacter baumannii, and the inhibition zone diameter increased progressively over time. This comprehensive study provides valuable insights into the molecular characteristics of P. pentosaceus ENM104, emphasizing its potential as a probiotic. Its notable cholesterol-lowering, GABA-producing, and antimicrobial capabilities suggest promising applications in the pharmaceutical and food industries. Future research should focus on further exploring these functional properties and assessing the strain's efficacy in clinical settings.