State Key Laboratory of Dairy Biotechnology, Shanghai Engineering Research Center of Dairy Biotechnology, Dairy Research Institute, Bright Dairy & Food Co., Ltd, Shanghai, 200436, China.
State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China.
Biol Trace Elem Res. 2024 Feb;202(2):671-684. doi: 10.1007/s12011-023-03693-1. Epub 2023 May 10.
Heavy metal pollution has become one of the most important global environmental issues. The human health risk posed by heavy metals encountered through the food chain and occupational and environmental exposure is increasing, resulting in a series of serious diseases. Ingested heavy metals might disturb the function of the gut barrier and cause toxicity to organs or tissues in other sites of the body. Probiotics, including some lactic acid bacteria (LAB), can be used as an alternative strategy to detoxify heavy metals in the host body due to their safety and effectiveness. Exopolysaccharides (EPS) produced by LAB possess varied chemical structures and functional properties and take part in the adsorption of heavy metals via keeping the producing cells vigorous. The main objective of this paper was to summarize the roles of LAB and their EPS in the adsorption and detoxification of heavy metals in the gut. Accumulated evidence has demonstrated that microbial EPS play a pivotal role in heavy metal biosorption. Specifically, EPS-producing LAB have been reported to show superior absorption, tolerance, and efficient abatement of the toxicity of heavy metals in vitro and/or in vivo to non-EPS-producing species. The mechanisms underlying EPS-metal binding are mainly related to the negatively charged acidic groups and unique steric structure on the surface of EPS. However, whether the enriched heavy metals on the bacterial cell surface increase toxicity to local mammal cells or tissues in the intestine and whether they are released during excretion remain to be elucidated.
重金属污染已成为全球最重要的环境问题之一。通过食物链以及职业和环境暴露而接触到的重金属对人类健康构成的威胁日益增加,导致一系列严重疾病。摄入的重金属可能会扰乱肠道屏障的功能,并对体内其他部位的器官或组织造成毒性。由于安全性和有效性,益生菌,包括一些乳酸菌(LAB),可用作宿主体内重金属解毒的替代策略。LAB 产生的胞外多糖(EPS)具有多样的化学结构和功能特性,通过使产生细胞保持活力来参与重金属的吸附。本文的主要目的是总结 LAB 及其 EPS 在肠道中重金属吸附和解毒中的作用。有充分的证据表明,微生物 EPS 在重金属生物吸附中起着关键作用。具体而言,已报道 EPS 产生的 LAB 在体外和/或体内对非 EPS 产生的物种表现出优越的吸收、耐受和有效减轻重金属毒性的能力。EPS-金属结合的机制主要与 EPS 表面带负电荷的酸性基团和独特的空间结构有关。然而,细菌细胞表面上富集的重金属是否会增加对肠道内局部哺乳动物细胞或组织的毒性,以及它们在排泄过程中是否会被释放,仍有待阐明。