Metagenomic analysis and antibacterial activity of kefir microorganisms

Abstract

The microbiota composition of kefir grain and milk kefir was assessed via a metagenomic approach. Significant microorganisms were isolated and identified using molecular methods. A safety assessment was conducted based on antibiotic susceptibility and blood hemolysis. Probiotic traits such as resistance to gastric tract conditions, surface characteristics, adhesion to intestinal cells, and antibacterial activity were also assessed. Metagenomic analysis revealed that kefir grains are a more stable community with clear dominant species as compared to milk kefir. Lactobacillus kefiranofaciens BDGO‐A1, Lactobacillus helveticus BDGO‐AK2, and Lactobacillu kefiri strains showed tolerance to acidic pH and the presence of bile salts, adhesion capability to Caco‐2 cells, in vitro antibacterial activity, and the production of antibacterial proteins. In the metagenomic analysis, contigs associated with these species showed the presence of genes involved in exporting polyketide antibiotics and bacteriocin production. To fully exploit the potential probiotic properties of these microorganisms to help human health, further investigation is necessary to elucidate the mechanisms behind the biological activity and the genotypic characteristics of the isolated strains.

Enhanced probiotic potential of Lactobacillus kefiranofaciens OSU-BDGOA1 through co-culture with Kluyveromyces marxianus bdgo-ym6

“…Lactobacillus kefiranofaciens OSU-BDGOA1 was previously identified by PCR amplification of a major part of the 16 s rRNA gene, as described in González-Orozco et al (2023) . Identity confirmation was performed by whole genome sequencing (BioSample ID: SAMN31370630).…”

“…Several strains of L. kefiranofaciens isolated from various kefir grain origins have shown probiotic traits; however, genotypic characterization is restricted due to the limited number of genome sequences available. Lactobacillus kefiranofaciens OSU-BDGOA1 (GenBank number: JARJVW01) is a strain previously isolated by our group and has shown activity against indicator microorganisms, resistance to gastrointestinal tract conditions, lack of blood hemolysis, and absence of antibiotic resistance to common antibiotics ( González-Orozco et al, 2023 ).…”

“…Kluyveromyces marxianus bdgo-ym6 (GenBank number: MZ927822.1) was previously isolated by our group from kefir grains. In a preliminary screening, this strain showed potential in resisting gastrointestinal tract conditions, surface hydrophobicity, auto-aggregation ability, and proteolytic activity ( González-Orozco et al, 2023 ).…”

Draft genome sequence of Lactobacillus helveticus OSU-BDGOAK2 and Lactobacillus kefiranofaciens OSU-BDGOA1, kefir grain isolates with potential antibacterial activity

“…Lactobacillus helveticus is an important inhabitant of kefir with reported production of antimicrobial peptides ( 4 ). L. helveticus OSU-BDGOAK2 and L. kefiranofaciens OSU-BDGOA1 were previously isolated from kefir grains and identified by amplification of the 16S rRNA gene, both strains exhibited in vitro antibacterial activity ( 5 ).…”