Isolation of Lactic Acid Bacteria from Naturally Ensiled Rosa roxburghii Tratt Pomace and Evaluation of Their Ensiling Potential and Antioxidant Properties

This study isolated five acid-producing strains (XQ1 and YZ1–YZ4) from naturally fermented pomace of Rosa roxburghii Tratt (RRT) in Guizhou’s karst region. Genetic and phenotypic analyses identified XQ1, YZ2, and YZ4 as Lactobacillus plantarum (L. plantarum), YZ3 as Weissella cibaria, and YZ1 as Bacillus licheniformis. A comparative evaluation with commercial strain AC revealed that XQ1, YZ2, and YZ4 exhibited superior acidification (reaching the stationary phase at 40 h) and tolerance to acidic conditions (pH 3.0), ethanol (6% v/v), bile salts (0.3%), and osmotic stress (6.5% NaCl), along with broad-spectrum antimicrobial activity against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Shigella dysenteriae, and Pseudomonas aeruginosa. Their cell-free supernatants (CFSs) showed comparable superoxide dismutase activity and total antioxidant capacity (2.54–2.66 FeSO4·7H2O eq mmol/L) to AC (2.68), with DPPH radical scavenging exceeding 50%. YZ3 displayed weaker acid production, tolerance, and limited antimicrobial effects. Safety assessments confirmed non-hemolytic activity and antibiotic susceptibility. In conclusion, the L. plantarum strains XQ1, YZ2, and YZ4 demonstrated strong ensiling potential and remarkable probiotic properties, establishing them as promising indigenous microbial resources for the preservation of RRT pomace and other food products.