新疆哈萨克酸马奶中功能性乳酸菌株的筛选、鉴定及功能评价

Screening, identification and functional evaluation of functional lactic acid bacteria strains in Xinjiang Kazakh koumiss

中文关键词:  发酵酸马奶  乳酸菌  胃肠道耐受性  抗氧化  高通量测序

英文关键词:koumiss  lactic acid bacteria  gastrointestinal tolerance  antioxidation  high-throughput sequencing

中文摘要:

      目的 从新疆哈萨克传统发酵酸马奶中筛选和鉴定益生性性乳酸菌, 并探究其胃肠道消化耐受性和抗氧化潜力。方法 通过稀释涂布平板法和生理生化鉴定来分离纯化乳酸菌属, 利用耐酸性和耐胆盐性筛选出潜在的胃肠道消化耐受性强的候选菌株, 采用体外模拟消化、硫酸铁铵比色法和甘油三酯(triglyceride, TG)试剂盒评估候选菌株的胃肠道存活率、降胆固醇能力和降甘油三酯能力。同时, 通过1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl, DPPH)自由基清除能力、2,2’-联氮-二(3-乙基-苯并噻唑啉-6-磺酸)二铵盐[2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) ammonium salt, ABTS]阳离子自由基清除能力和铁还原能力测试候选菌株的抗氧化潜力, 并与德式乳杆菌保加利亚亚种(Lactobacillus delbrueckii subsp. bulgaricus)进行比较分析。最后, 采用16S rRNA高通量测序对候选菌株进行精确鉴定。结果 从新疆哈萨克传统发酵酸马奶中分离纯化出96株菌株, 40株被鉴定为乳酸菌属。10株候选菌株表现出较高的耐酸性和耐胆盐性, 并被鉴定为鼠李糖乳杆菌(Lacticaseibacillus rhamnosus)、植物乳杆菌(Lactiplantibacillus plantarum)、戊糖乳杆菌(Lactiplantibacillus pentosus)和副干酪乳杆菌(Lacticaseibacillus paracasei)。其中, M2菌株(Lacticaseibacillus rhamnosus)表现出最佳的益生特性, 胆固醇和甘油三酯降解率高，模拟胃肠液中存活率高, 对DPPH和ABTS阳离子自由基的清除能力高于德式乳杆菌保加利亚亚种。结论 本研究成功从新疆哈萨克传统发酵酸马奶中筛选鉴定出高耐受性、高抗氧化性的L. rhamnosus M2, 为发掘和利用酸马奶中的功能性益生菌提供了理论依据。

英文摘要:

      Objective To isolate and identify functional strains of lactic acid bacteria from traditional fermented Kazakh koumiss in Xinjiang and explore their gastrointestinal tolerance and antioxidant potential. Methods The isolation and purification of lactic acid bacteria were conducted using dilution plate method and physiological and biochemical identification. Candidate strains with potential gastrointestinal tolerance were screened based on acid and bile salt tolerance. In vitro simulated digestion, ammonium iron sulfate colorimetry, and triglyceride (TG) kit were used to assess the gastrointestinal survival rate, cholesterol reduction, and triglyceride reduction capabilities of the strains. The antioxidant potential of the candidates was characterized through 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) ammonium salt (ABTS) cation radical scavenging, and iron-reducing abilities, and compared with Lactobacillus delbrueckii subsp. bulgaricus. Finally, 16S rRNA high-throughput sequencing was employed for precise identification of the candidate strains. Results A total of 96 strains were isolated and purified from traditional fermented Kazakh koumiss in Xinjiang, and 40 strains were identified as lactic acid bacteria. The 10 candidate strains showed high acid resistance and bile salt resistance, and were identified as Lacticaseibacillus rhamnosus, Lactiplantibacillus plantarum, Lactiplantibacillus pentosus and Lacticaseibacillus paracasei. Among them, M2 strain (Lacticaseibacillus rhamnosus) showed the best probiotic properties, with high degradation rate of cholesterol and triglyceride, high survival rate in simulated gastrointestinal fluid, and higher scavenging ability of DPPH radical scavenging and ABTS cation radical scavenging than Lactobacillus bulgaricus. Conclusion This study successfully identifies strains of Lactobacillus rhamnosus M2 with high tolerance and antioxidative properties from traditional fermented Kazakh koumiss in Xinjiang, providing a theoretical basis for the exploration and utilization of functional probiotic bacteria in fermented koumiss.