Functional and Probiotic Characterization of White Cheese-Derived Lentilactobacillus kefiri with Cholesterol-Lowering and Conjugated Linoleic Acid Producing Potential

This study aimed to molecularly characterize the MA3 strain isolated from traditional white cheese samples obtained from Erzurum province and to evaluate its multifaceted probiotic properties. Based on 16S rRNA analysis, the isolate was identified as Lentilactobacillus kefiri. The strain was assessed for safety, resistance to gastrointestinal conditions, antibiotic susceptibility, antimicrobial activity, bacteriocin production potential, vitamin B12 production, cholesterol-lowering capacity, and conjugated linoleic acid (CLA)-related genetic potential. Safety analyses demonstrated that MA3 exhibited γ-hemolytic properties and did not form biofilms. The strain maintained viability following pepsin and pancreatin–bile salt treatment. Antibiotic susceptibility testing indicated sensitivity to ampicillin, amoxicillin, and chloramphenicol. Antimicrobial assays revealed inhibitory activity against several pathogens, with the highest inhibition observed against Yersinia enterocolitica. Molecular screening detected amplification only in the plnEF gene region, indicating bacteriocin-associated potential. The MA3 strain also demonstrated vitamin B12 production and achieved an 80.3% cholesterol reduction rate, supported by molecular findings related to the CHO gene. In addition, detection of the CLA-associated gene region further supported the functional characteristics of the isolate. Overall, L. kefiri MA3 was identified as a promising candidate for application as a starter or probiotic culture in functional dairy products.