兰州甜胚子中乳酸菌的分离鉴定及益生特性研究

Isolation, Identification, and Probiotic Property Characterization of Lactic Acid Bacteria from Fermented Sweet Oats (Tianpeizi) in Lanzhou

摘要:

【目的】筛选优质的食源性乳酸菌。【方法】采用传统微生物培养方法结合16S rRNA测序对兰州甜胚子中的乳酸菌进行分离、纯化及鉴定，并从酸及胆盐耐受性、抗生素敏感性、抑菌活性和体外抗氧化活性等方面综合评价其益生特性。【结果】从兰州甜胚子中共分离鉴定出6株乳酸菌，分别为副干酪乳酪杆菌（Lacticaseibacillus paracasei）PR6、发酵粘液乳杆菌（Limosilactobacillus fermentum）PR10、类肠膜魏斯氏菌（Weissella paramesenteroides）PR13、戊糖片球菌（Pediococcus pentosaceus）PR15、乳酸片球菌（Pediococcus acidilactici）PR17和融合魏斯氏菌（Weissella confusa）PR18。益生特性结果表明，菌株PR10在酸性（pH 2.5和3.0）、胆盐环境下均有较高的存活率，对环丙沙星、氨苄西林、四环素和青霉素等常用抗生素具有中高度敏感性，且可有效抑制食源性致病菌（金黄色葡萄球菌和大肠埃希菌）；菌株PR18具有较好的抗氧化活性，其1，1-二苯基-2-三硝基苯肼（DPPH）自由基清除率和还原能力分别为67.6%和42.7%，且菌株PR18的酸及胆盐耐受性仅次于菌株PR10。【结论】发酵粘液乳杆菌PR10和融合魏斯氏菌PR18具有潜在的益生特性，可作为候选菌株开展进一步研究。

Abstract:

[Objective] This study aims to screen high-quality food-borne lactic acid bacteria. [Method] Lactic acid bacteria were isolated, purified, and identified from traditional fermented sweet oats (Tianpeizi) in Lanzhou by conventional microbial culture methods combined with 16S rRNA gene sequencing. The probiotic properties of the isolates were comprehensively evaluated based on acid and bile salt tolerance, antibiotic susceptibility, antibacterial activity, and in vitro antioxidant capacity. [Result] A total of six strains of lactic acid bacteria were isolated and identified from Tianpeizi in Lanzhou, including Lacticaseibacillus paracasei (L. paracasei) PR6, Limosilactobacillus fermentum (L. fermentum) PR10, Weissella paramesenteroides (W. paramesenteroides) PR13, Pediococcus pentosaceus (P. pentosaceus) PR15, Pediococcus acidilactici (P. acidilactici) PR17, and Weissella confusa (W. confusa) PR18. The probiotic property assay showed that strain PR10 exhibited high survival rates under acidic conditions (pH 2.5 and 3.0) and in the presence of bile salts. It showed moderate to high susceptibility to commonly used antibiotics, including ciprofloxacin, ampicillin, tetracycline, and penicillin, and demonstrated strong inhibitory activity against foodborne pathogens (Staphylococcus aureus and Escherichia coli). Strain PR18 displayed notable antioxidant activity, with 1,1-diphenyl-2-trinitrophenylhydrazine (DPPH) free radical scavenging rate and reducing power of 67.6% and 42.7%, respectively. In addition, strain PR18 showed good acid and bile salt tolerance, second only to strain PR10. [Conclusion] L. fermentum PR10 and W. confusa PR18 exhibit promising probiotic potential and may serve as candidate strains for further studies.