Investigation of Probiotic Properties of Lacticaseibacillus casei 4 N-6 Strain Isolated From Cow Milk.

The aim of the present study was to characterize the probiotic potential of Lacticaseibacillus casei 4 N-6 strain isolated from cow's milk. For this purpose, acid, bile salt, pancreatin, pepsin, phenol, and lysozyme tolerance, co-aggregation and auto-aggregation properties, phytase production, antibiotic resistance, and antibacterial properties were analyzed in vitro. The strain had relatively poor acid, bile salt, and pepsin tolerance. However, the strain showed a high pancreatin, lysozyme, and phenol tolerance. In addition, it exhibited moderate co-aggregation with E. coli and good autoaggregation. Furthermore, the cell-free supernatant of Lb. casei 4 N-6 showed a high antimicrobial activity against Bacillus cereus (N32), Salmonella enteritidis (RK-485), and Enterococcus faecalis (RK-487). 4 N-6 was resistant to vancomycin, teicoplanin, gentamicin, and ceflazidime. The 4 N-6 strain did not show hemolytic activity. In addition, this strain was found to be able to produce phytase. All the findings obtained indicate that Lb. casei 4 N-6 is promising as a potential probiotic candidate and has superior properties that can be evaluated as a probiotic in the future. However, further research and in vivo studies are needed to fully understand its mechanism of action and optimize its use as a probiotic.