Abstract:[Objective] This study aims to screen high-quality food-borne lactic acid bacteria. [Method] Lactic acid bacteria were isolated, purified, and identified from traditional fermented sweet oats (Tianpeizi) in Lanzhou by conventional microbial culture methods combined with 16S rRNA gene sequencing. The probiotic properties of the isolates were comprehensively evaluated based on acid and bile salt tolerance, antibiotic susceptibility, antibacterial activity, and in vitro antioxidant capacity. [Result] A total of six strains of lactic acid bacteria were isolated and identified from Tianpeizi in Lanzhou, including Lacticaseibacillus paracasei (L. paracasei) PR6, Limosilactobacillus fermentum (L. fermentum) PR10, Weissella paramesenteroides (W. paramesenteroides) PR13, Pediococcus pentosaceus (P. pentosaceus) PR15, Pediococcus acidilactici (P. acidilactici) PR17, and Weissella confusa (W. confusa) PR18. The probiotic property assay showed that strain PR10 exhibited high survival rates under acidic conditions (pH 2.5 and 3.0) and in the presence of bile salts. It showed moderate to high susceptibility to commonly used antibiotics, including ciprofloxacin, ampicillin, tetracycline, and penicillin, and demonstrated strong inhibitory activity against foodborne pathogens (Staphylococcus aureus and Escherichia coli). Strain PR18 displayed notable antioxidant activity, with 1,1-diphenyl-2-trinitrophenylhydrazine (DPPH) free radical scavenging rate and reducing power of 67.6% and 42.7%, respectively. In addition, strain PR18 showed good acid and bile salt tolerance, second only to strain PR10. [Conclusion] L. fermentum PR10 and W. confusa PR18 exhibit promising probiotic potential and may serve as candidate strains for further studies.
