Characterization of an EPS-producing bifidobacterial strain based on integration of phenotypic and complete genome sequencing data
Characterization of an EPS-producing bifidobacterial strain based on integration of phenotypic and complete genome sequencing data
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DOI：
10.1139/cjm-2023-0025
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发表时间：
2023-06-23
影响因子：
2.8
通讯作者：
Wei，Yanxia
中科院分区：
文献类型：
--
作者：
Liu，Dianbin;Huang，Haohan;Wei，Yanxia
双歧杆菌和乳酸杆菌是人体肠道菌群的常见成员，在维持宿主肠道微环境的稳态中起着重要作用。几种双歧杆菌和乳酸杆菌菌株已被用作有益于健康的益生菌。双歧杆菌和乳酸杆菌产生的胞外多糖被认为是介导这些有益效应的有益性状。本研究从健康婴幼儿粪便中分离到双歧杆菌属和乳杆菌属的21株菌株，并对其产EPS能力进行了筛选。在这些菌株中，长双歧杆菌XZM 1表现出最高的EPS产量，这是进一步证实和表征。对菌株XZM 1的全基因组进行测序，其揭示了用于EPS产生的基因簇的存在。此外，还对XZM 1与其他B. longumspecies.纯化后，通过凝胶渗透色谱法测定来自XZM 1的EPS的分子量（Mw）为4023 Da（Mw）。对EPS水解产物的分析表明，EPS由甘露糖、葡萄糖、半乳糖、阿拉伯糖和岩藻糖组成。此外，EPS对羟基自由基的清除能力高于1，1-二苯基-2-苦肼基自由基。总体而言，这些结果表明，XZM 1从B. longumspecies可能是一种有前途的益生菌候选者。
BifidobacteriumandLactobacillusare known to be common members of the human intestinal microbiota, which play important roles in maintaining the homeostasis of host gut microenvironment. Several bifidobacterial and lactobacilli strains have been used as probiotics for health benefits. The exopolysaccharides (EPSs) produced by strains fromBifidobacteriumandLactobacillusare considered as beneficial traits mediating these beneficial effects. In this study, 21 strains belonging toBifidobacteriumandLactobacilluswere isolated from healthy infants’ stool and were screened for EPS-producing ability. Among these strains,Bifidobacterium longumXZM1 showed the highest EPS productivity, which was further confirmed and characterized. The complete genome of strain XZM1 was sequenced, which revealed the presence of a gene cluster for EPS production. Furthermore, comparative genome analysis was performed among XZM1 and other strains fromB. longumspecies. Following purification, the molecular weight (Mw) of EPS from XZM1 was determined as 4023 Da (Mw) through gel permeation chromatography. Analysis of the EPS hydrolysates revealed that the EPS was composed of mannose, glucose, galactose, arabinose, and fucose. Additionally, the EPS exhibited higher scavenging abilities toward hydroxyl than 1,1-diphenyl-2-picrylhydrazyl free radical. Overall, these results suggest that XZM1 fromB. longumspecies may be a promising probiotic candidate.