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.