Screening and Functional Characterization of Lactic Acid Bacteria for Alleviating Hyperuricemia in the Intestine of Trachemys scripta elegans

This study aimed to screen lactic acid bacteria (LAB) with uric acid-regulating potential from the gut microbiota of Trachemys scripta elegans and systematically evaluate their functional characteristics. The selective culture medium with uric acid as the sole carbon and nitrogen source was established for primary screening, combined with in vitro uric acid (UA) degradation activity test and xanthine oxidase (XOD) inhibition experiment for secondary screening. Finally, two dominant strains were identified by 16S rDNA sequencing, and their functional characteristics were characterized. Results demonstrated that strains Enterococcus hirae YL-3 and Enterococcus durans YL-8 exhibited UA degradation rates of 83.83% and 85.48%, respectively, along with XOD inhibition rates of 71.72% and 65.79%, indicating significant hypouricemic potential. Additionally, strain YL-3 exhibited excellent fermentation and probiotic characteristics. In media with 6% NaCl, it achieved an OD₆₀₀ of 0.76, outperforming the blank group's 0.55 (P<0.05). It also showed a survival rate of 75.46% under pH3.0 conditions and 99.53% in the presence of 0.3% bile salts; Its autoaggregation rate was 89.38%. Strain YL-8 demonstrated strong antioxidant activity, with its fermentation supernatant achieving DPPH·, ABTS⁺·, and ·OH scavenging rates of 60.22%, 93.66%, and 99.25%, respectively. In this study, LAB with high uric acid degradation ability and xanthine oxidase activity were isolated from the intestine of Trachemys scripta elegans for the first time, which provided theoretical basis for developing probiotic system to alleviate hyperuricemia.