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Journal of Zhejiang University SCIENCE B
ISSN 1673-1581(Print), 1862-1783(Online), Monthly
2021 Vol.22 No.7 P.533-547
Screening beneficial bacteriostatic lactic acid bacteria in the intestine and studies of bacteriostatic substances
Abstract: Lactic acid bacteria (LAB) are a representative probiotic. As the dominant flora in the human intestinal tract, LAB can regulate the balance of human intestinal flora and improve host health. The purpose of this study was to isolate and screen LAB that are well suited to the intestinal characteristics of the Chinese population, with excellent probiotics and high antibacterial activity. After 16S ribosomal RNA (rRNA) homology and phylogenetic tree analysis, potential probiotics were tested for their antibacterial activity, resistance to artificial gastrointestinal fluid and drugs, surface hydrophobicity, and safety. Three strains of LAB with acid resistance, bile salt resistance, epithelial cell adhesion, and no multidrug resistance were selected: Lactobacillus salivarius, Leuconostoc lactis, and Lactobacillus paracasei. Analysis of the antibacterial active substances in the three strains and their fermentation broths revealed that the main antibacterial substances of L. lactis were organic acids, whereas those of L. salivarius and L. paracasei were organic acids and bacteriocins with broad-spectrum antibacterial activity. These three strains of probiotic LAB with high antibacterial activity were identified as bacterial resources that could potentially be used to develop probiotic preparations for the prevention and treatment of intestinal diseases caused by intestinal pathogens.
Key words: Intestinal lactic acid bacteria; Screening; Probiotic; Bacteriostatic substance
创新点:从中国健康成人粪便中分离出了具有良好潜在益生性和安全性的乳酸菌,发现了其对大肠杆菌和金黄色葡萄球菌有较高的抑菌活性。同时探究出了乳酸明串珠菌的主要抑菌物质为有机酸,唾液乳杆菌和副干酪乳杆菌的主要抑菌物质为有机酸和细菌素,而且该细菌素具有广谱的抗菌活性。
方法:通过分离纯化、菌株形态学鉴定、16SrRNA同源性和系统发育树分析初步鉴定乳酸菌;采用牛津杯双层琼脂扩散法筛选出抑菌乳酸菌;通过人工模拟胃肠液和药敏试纸法评价乳酸菌的潜在益生性和耐药性;通过不同酶、pH和热处理对益生性乳酸菌的抑菌物质及性质进行分析;采用双水相萃取法对抑菌物质进行纯化;最后通过Tricine-SDS-PAGE电泳对抑菌物质分子量进行预测及抑菌普测定。
结论:从中国健康成人的粪便中分离筛选出3株具有良好潜在益生性和安全性的乳酸菌菌株,对大肠杆菌ATCC 25922和金黄色葡萄球菌ATCC 25923均有较好的抑菌活性。乳酸明串珠菌的主要抑菌物质为有机酸,唾液乳杆菌和副干酪乳杆菌的主要抑菌物质为有机酸和广谱抑菌活性的细菌素。
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DOI:
10.1631/jzus.B2000602
CLC number:
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On-line Access:
2024-08-27
Received:
2023-10-17
Revision Accepted:
2024-05-08
Crosschecked:
2022-04-22