一株强抑菌活性植物乳杆菌的分离及益生性能研究

以健康黔北黑猪肠道黏膜内容物为原料，采用厌氧罐培养法分离出肠道细菌，结合抑菌试验筛选出其中具有强抑菌活性菌种进行分子生物学鉴定，并对其耐受性及抑菌物质的稳定性进行研究。结果表明，该菌株被鉴定为植物乳杆菌（Lactobacillus plantarum），对金黄色葡萄球菌ATCC6538、大肠埃希氏菌ATCC25922和鼠伤寒沙门氏菌ATCC14028等指示菌具有强抑制作用，其发酵上清液对3种指示菌的最大抑菌圈直径分别约为44.7 mm、23.1 mm和31.8 mm；菌株发酵上清液抑菌物质耐高温，120 ℃处理30 min抑菌活性无显著变化（P＞0.05）；胰蛋白酶处理后，上清液的抑菌圈直径显著减小（P＜0.05），而过氧化氢酶和胃蛋白酶处理后抑菌圈直径无显著变化（P＞0.05），表明主要抑菌物质为有机酸和活性肽；菌株经pH 2、0.3%猪胆盐或人工胃肠液处理6 h后存活率分别为0.06%、0.61%、40.80%和25.65%，显示出良好的益生性能。

Isolation and probiotic property of a Lactobacillus plantarum strain with strong antimicrobial activity

Intestinal bacteria were isolated from the intestinal mucosa contents of healthy Qianbei black pigs by anaerobic tank culture. Combined with the antibacterial test, the strains with strong antibacterial activity were screened and identified by molecular identification. The tolerance and stability of antibacterial substances of the strain were studied. The results indicated that the strain was identified as Lactobacillus plantarum, and it showed strong bacteriostatic activity to Staphylococcus aureus ATCC6538, Escherichia coli ATCC25922, and Salmonella enterica ATCC14028. The maximum inhibition zone diameters of the L. plantarum supernatant towards the three strains were about 44.7 mm, 23.1 mm and 31.8 mm, respectively. The antimicrobial substances in the supernatant of strain fermentation were resistant to high temperature, and the antimicrobial activity had little change after treatment at 120 ℃ for 30 min (P＞0.05). The inhibition zone diameter was significantly reduced after treatment with trypsin (P＜0.05), and there was no significant change in inhibition zone diameter after catalase and pepsin treatment (P＞0.05), indicating the main bacteriostatic substances were organic acids and active peptides. After treated with pH 2, 0.3% pig bile salt or artificial gastric fluid for 6 h, the survival rates of the strain were 0.06%, 0.61%, 40.80% and 25.65%, respectively, which exhibited excellent probiotic properties.