微生物胞外多糖在修复重金属污染中的潜力及其生物化学机制

Potential of microbial extracellular polysaccharides in the bioremediation of heavy metals and the underlying biochemical mechanism

微生物常常通过分泌细胞外多糖类物质(胞外多糖)来保护细胞免受极端环境条件、不利因素(如干燥、高盐、辐射、高低温、强酸碱)以及有毒有害物质(如重金属等)的损伤。胞外多糖在微生物耐受和降低重金属污染中起重要作用,在环境科学研究中有重要意义。本文综述了微生物胞外多糖的生物化学性质,简述了重金属对微生物胞外多糖合成及其结构的影响,从生物吸附、生物转化两个方面总结了微生物胞外多糖降低环境重金属污染的生物化学机制,最后展望了未来的研究方向和有待解决的科学问题。

Microorganisms secrete polysaccharides or extracellular polymeric substance to protect themselves from extreme or harmful environmental conditions, such as drought, high salinity, radiation, high or low temperature, acid or alkalinity, and harmful substance such as heavy metals. Specifically, extracellular polysaccharides play essential roles in microbial resistance to or remediation of heavy metals. This review summarized the general biochemical properties of microbial extracellular polysaccharides, described the influence of heavy metals on the synthesis of microbial extracellular polysaccharide and their structures, and specifically, reviewed the biochemical mechanisms underlying the biosorption and biotransformation of heavy metals by microbial extracellular polysaccharide. Finally, we discussed the unsolved scientific questions and proposed the future research directions.