| 摘要: |
| 目的：金黄色葡萄球菌（Staphylococcus aureus）是重要的食源性致病菌之一，筛选出对S. aureus有高效拮抗菌活性的乳酸菌，并考察其抑菌活性和优化发酵条件。方法：以S. aureus为指示菌，筛选出具有高效抑菌活性的乳酸菌，综合形态学、生理生化及16S rRNA基因序列分析对菌株进行鉴定；对该菌株无细胞上清液（Cell-free supernatant，CFS）中抑菌物质的耐热性、耐pH、酶敏感性等性质进行研究；利用单因素和正交试验对菌株抑菌物质发酵工艺（碳源、氮源、无机盐成分、吐温浓度、发酵初始pH、接种量、温度和时间等）进行优化。结果：获得一株可高效拮抗S. aureus的乳酸菌S13，鉴定为植物乳植杆菌（Lactiplantibacillus plantarum）；该菌株的CFS在pH 3.0-7.0的范围内对S. aureus具有抑菌活性，可耐高温（40-121 ℃），且CFS抑菌活性可被多种蛋白酶完全消除，初步推断该菌株所产抑菌物质为多肽/蛋白类细菌素。优化获得产抑菌物质最佳发酵工艺为：初始pH为6.5，温度为36 ℃，时间为24 h、接种量为3%（v/v），碳源为20 g/L的蔗糖，氮源为19 g/L玉米浆，无机盐为9.25 g/L硫酸锰，吐温添加量为3 mL/L。在此发酵条件下，CFS的抑制活性较优化发酵前提高了14.61%。结论：筛选得到的L. plantarum S13对S. aureus具有良好的拮抗活性，安全性高，可作为新型食品防腐菌株资源。 |
| 关键词: 金黄色葡萄球菌 植物乳植杆菌 拮抗菌 正交试验 发酵条件优化 |
| DOI： |
| 投稿时间：2026-04-29修订日期：2026-08-04 |
| 基金项目: |
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| Screening of Lactic Acid Bacteria with Antagonistic Activity against Staphylococcus aureus and Optimization of Fermentation Conditions |
|
shen nai kun
|
| (Guangxi Minzu University) |
| Abstract: |
| Objective: Staphylococcus aureus is a major foodborne pathogenic bacterium. This study aimed to screen lactic acid bacteria (LAB) exhibiting potent antagonistic activity against S. aureus, characterize their inhibitory activity, and optimize the fermentation conditions for maximal production of inhibitory metabolites. Methods: Using S. aureus as the indicator bacterium, LAB isolates exhibiting potent inhibitory activity were screened via agar well diffusion assays. Strain identification was conducted through integrated analysis of morphological, physiological, and biochemical characteristics, supplemented by 16S rRNA gene sequencing. The physicochemical properties, including thermal stability, pH stability, and enzyme sensitivity to proteolytic enzymes, of the inhibitory compounds present in the cell-free supernatant (CFS) were systematically evaluated. To optimize key fermentation parameters governing inhibitory metabolite production, a two-stage experimental strategy was employed: initial single-factor experiments followed by an orthogonal experimental design. The parameters investigated included carbon and nitrogen sources, inorganic salt composition, Tween-80 concentration, initial pH, inoculum size, incubation temperature, and fermentation duration. Results: A highly antagonistic LAB strain, designated S13, was isolated and identified as Lactiplantibacillus plantarum. Its CFS demonstrated broad pH stability (retaining full activity across pH 3.0-7.0), maintained complete inhibitory activity after heat treatment at 40-121?°C for 15?min, and lost all activity upon exposure to proteolytic enzymes, including trypsin, pepsin, and proteinase K, strongly indicating that the active inhibitory compounds are peptide- or protein-based bacteriocins. The optimized fermentation conditions were determined as follows: initial pH 6.5; incubation temperature 36?°C ; fermentation duration 24?h; inoculum size 3% (v/v); carbon source 20?g/L sucrose; nitrogen source 19?g/L corn steep liquor; inorganic salt 9.25?g/L; MnSO?·H?O 9.25 g/L; and Tween-80 supplementation 3?mL/L. Under these optimized conditions, the inhibitory activity of the CFS increased by 14.61% relative to that obtained under unoptimized baseline conditions. Conclusion: The isolated L. plantarum S13 exhibits robust and broad-spectrum antagonism against S. aureus, displays favorable safety attributes, and holds considerable promise as a novel, natural preservative strain for food applications. |
| Key words: Staphylococcus aureus Lactiplantibacillus plantarum antagonistic bacteria orthogonal test optimization of fermentation conditions |
