降解尿酸乳酸菌复合菌系的筛选与菌株组合提升降解效果

【背景】高尿酸症由血液中尿酸含量明显升高而导致，利用乳酸菌对人体的益生作用缓解高尿酸血症越来越受到关注。【目的】获得具有降解尿酸能力的乳酸菌复合菌系与纯培养菌株。【方法】以泡菜为样品来源，以尿酸为底物，采用MRS培养基筛选降解尿酸的乳酸菌复合菌系，通过高效液相色谱法测定复合菌系对尿酸的降解能力。【结果】得到一组乳酸菌复合菌系，当培养温度为37 °C、pH值为6.20、静置培养72 h后复合菌系对尿酸的降解率为12.08%；通过优化培养条件，当该菌系在以牛肉膏为单一氮源、初始pH值为5.00、温度为35 °C的条件下培养72 h，尿酸降解率上升至17.19%，降解率比优化前提高了42.3%；从该菌系中分离出两株具有尿酸降解能力的菌株UA-1与UA-2，它们的尿酸降解率分别为10.85%和8.65%；通过形态学观察和16S rRNA基因序列分析，经鉴定两株菌均为布氏乳杆菌(Lactobacillus buchneri)。将两株单菌组合降解尿酸试验发现，UA-1与UA-2比例为2:1的尿酸降解率为20.2%，比原复合菌系的降解能力提高了67.22%。【结论】研究证明了乳酸菌复合菌系对尿酸的降解能力优于单个菌株，为后续利用乳酸菌复合菌系应用提供了数据支持。

Screening of uric acid-degrading lactic acid bacteria consortium and strain combination for enhancing degradation

Background] Hyperuricemia is caused by a significant increase the content of uric acid in the blood, and using probiotic lactic acid bacteria to relieve hyperuricemia has attracted more and more attention. Objective] To obtain the lactic acid bacteria consortium and pure culture strains with the ability to degrade uric acid. Methods] We used the MRS medium with uric acid as the substrate to isolate the consortium of lactic acid bacteria degrading uric acid from kimchi. Further, we determined the uric acid degradation ability of the consortium by high performance liquid chromatography. Results] A consortium of lactic acid bacteria was obtained. After being cultured at 37 °C and pH 6.20 for 72 h, the consortium showed the degradation rate of 12.08% for uric acid. Moreover, after optimization of degradation conditions, the degradation rate was increased to 17.19% after inoculation 72 h under the conditions of beef extract as the single nitrogen source, initial pH 5.00, and 35 °C, and the degradation rate increased by 42.3% compared with that before optimization. Two strains UA-1 and UA-2 with uric acid degradation ability were isolated from the consortium, and their uric acid degradation rates were 10.85% and 8.65%, respectively. The two strains were identified as Lactobacillus buchneri based on morphological characteristics and 16S rRNA sequence. The combination of UA-1 and UA-2 at a ratio of 2:1 showed the uric acid degradation rate of 20.2%, which was 67.22% higher than that of the consortium. Conclusion] This study proved that the combination of lactic acid bacteria had better degradation effect on uric acid than single strains, which provided data support for the subsequent application use of lactic acid bacteria consortium.