Safety-Filtered Characterization of Lentilactobacillus farraginis TV3.1.2: an Autochthonous Probiotic Candidate from Vietnamese Solanum macrocarpon Ferments

Abstract

Although the traditional plant-based fermented food groups are important sources of microbial biodiversity, the functional and safety properties of many autochthonous species are poorly studied. The present study aimed to characterize Lentilactobacillus farraginis TV3.1.2, an indigenous isolate from Vietnamese Solanum macrocarpon (Ca phao muoi chua) and investigate its potential as an alternative to the use of antibiotic growth promoters in livestock. Based on a systematic 5-stage screening of 62 isolates, TV3.1.2 was detected by 16S rRNA gene sequencing. The strain was found to be highly resilient, with >2 Log CFU/mL remaining viable at pH 2.0 (2.29±0.49 Log CFU/mL) and 1.0% bile salts (3.50±0.61 Log CFU/mL). Moreover, TV3.1.2 displayed broad-spectrum antimicrobial activity with an inhibition zone of 30.47 mm against Staphylococcus aureus, which is indicative of the production of bacteriocin-like substance. Safety testing confirmed a non-hemolytic profile and susceptibility to clinically relevant antibiotics. No virulence factors (esp, gelE, cylA/M), vancomycin resistance genes (vanA/B), and biogenic amine determinants (hdc1/2, tdc) were detected by genotypic analysis. Overall, these results suggest that L. farraginis TV3.1.2 could serve as a safe and protective starter culture in food and agriculture applications compared to pathogenic lines.