The L. plantarum strain previously isolated in the Applied and Environmental Microbiology Research Group was preserved in cryovials Cryioinstant (Ref: 409113/6, Deltalab S.L., Spain) in the − 80 °C freezer. The microorganism was recovered by incubating two porous beads in 30 mL of MRS broth (Ref: BK070HA, Biokar Diagnostics, France) for 24 h at 37 °C in aerobic environment.
After the incubation period, a serial dilution was prepared up to the concentration of 10–8. From the dilution bank, MRS agar (Ref: BK089HA, Biokar Diagnostics, Francia) was seeded to establish the concentration of the microorganism and a blood agar (Ref: 254005, Becton Dickinson, Germany) was also seeded to evaluate its possible hemolytic capacity. Plates were incubated at 37 °C for 24 h, in aerobic environment.
So, to corroborate the absence of contamination throughout the preservation period, the strain was identified by phenotypic and molecular tests.
The tests carried out for phenotypical identification were Gram stain, spore stain and enzymatic tests of Catalase and Oxidase (Ref: 55 635, bioMérieux SA, France). The methodologies used have been the traditional in Microbiology16 .
Then, an API 50 CH gallery (Ref: 50 300, bioMérieux SA, France) was inoculated with API 50 CHL Medium (Ref: 50 410, bioMérieux SA, France) to corroborate the identification of the strain.
After the incubation period, a serial dilution was prepared up to the concentration of 10–8. From the dilution bank, MRS agar (Ref: BK089HA, Biokar Diagnostics, Francia) was seeded to establish the concentration of the microorganism and a blood agar (Ref: 254005, Becton Dickinson, Germany) was also seeded to evaluate its possible hemolytic capacity. Plates were incubated at 37 °C for 24 h, in aerobic environment.
So, to corroborate the absence of contamination throughout the preservation period, the strain was identified by phenotypic and molecular tests.
The tests carried out for phenotypical identification were Gram stain, spore stain and enzymatic tests of Catalase and Oxidase (Ref: 55 635, bioMérieux SA, France). The methodologies used have been the traditional in Microbiology16 .
Then, an API 50 CH gallery (Ref: 50 300, bioMérieux SA, France) was inoculated with API 50 CHL Medium (Ref: 50 410, bioMérieux SA, France) to corroborate the identification of the strain.