In vitro evaluation of probiotic and antioxidant potential of Lacticaseibacillus paracasei ED25

This study aimed to assess the in vitro probiotic and antioxidant potential of lactic acid bacteria (LAB) isolated from different white cheeses, also known as “Beyaz Peynir” in Turkey. A total of 58 bacterial strains were isolated from 11 different white cheeses obtained from small-scale dairies. According to some preselection criteria (having the distinctive features of LAB, exhibiting non-haemolytic property, and resisting the simulated gastrointestinal conditions such as low pH, pepsin, pancreatin and bile salt tolerance), four (ED13, ED20, ED25 and ED36) out of 58 isolates were selected for the subsequent experiments. Among the four isolates, ED25 exhibited the maximum lactase production and cholesterol removal potential, the highest biological activity (antimicrobial and antioxidant activity) and the lowest antibiotic resistance. In addition, the second highest B12-producing capacity were measured for ED25. The isolate ED25 was found to possess antimicrobial effectiveness against all tested microorganisms (S. aureus, E. coli, S. Typhimurium, L. monocytogenes and C. albicans) according to the agar well diffusion method. In vitro antioxidant activity assay demonstrated that the culture supernatant of the ED25 had the ability to scavenge DPPH (49%), ABTS (37%), OH• (51%) and O₂^•– (38%) radicals. According to the sequences analysis of the 16 S rRNA gene, the isolate ED25 was identified as Lacticaseibacillus paracasei (GenBank accesion number: OP036674.1). Due to strong biological activities, L. paracasei ED25 may be used as a probiotic agent against gastrointestinal disorders, infections and oxidative stress-mediated diseases.