铁细菌胞外多聚物对铁矿物的调控形成及其环境意义

Regulating formation of iron minerals by iron bacteria/EPS and its environmental significance

环境介质溶液中铁的水解作用和稳定化作用主要受铁细菌及其代谢有机物质的影响。铁细菌普遍存在于自然环境中,可利用低价铁源为自身生长所需能量。铁细菌胞外有机物的主要组分如多糖和蛋白质等可与铁结合,并通过氧化或沉淀作用使铁稳定、沉积而形成铁矿物;此外铁细菌胞外多聚物可催化铁的氧化或促进铁的聚集。这些生物成因铁矿物因具有良好的表面吸附与氧化还原等化学活性,及有效固定环境中的重金属、放射性核素和催化降解有机污染物的良好环境属性,在环境生物矿物材料和环境治理研究领域被日益重视。故本文基于铁细菌及其胞外多聚物对铁矿物矿化形成的重要调控作用,介绍了环境中存在的铁细菌及其生物矿化特征,重点阐述了铁细菌胞外多聚物(组分、结构及特性)及其在铁矿物矿化过程中的作用,同时对铁细菌胞外多聚物及生物成因铁矿物的环境意义进行了概述。

Hydrolization and stabilization of iron in environmental media are usually impacted by iron bacteria and their metabolization substances.Iron bacteria are commonly present in natural environments and can use ferrous iron as energy sources for their growth.Bacteria producing extracellular polymeric substances （EPS） mainly including polysaccharides and proteins can combine ferrous iron.The combined ferrous iron can further be biooxidized and precipitated into iron minerals.Moreover,bacteria/EPS can catalyze Fe2 ＋ bio-oxidization and promote Fe assembly.The biological iron minerals have good chemical properties such as surface adsorption and oxidization-reduction,and good environmental attributes including effective fixation of heavy metals and radioactive nuclides,and catalytic degradation of organic contaminations.So these biological iron minerals play an important role in the study of environmental and biological mineral materials as well as in the treatment of polluted circumstances.Based on the key regulation action on bio-mineralization of iron by bacteria/EPS,the authors introduced iron bacteria and their biological mineralization characteristics in the environment,and mainly described the composition,structure and attribute of EPS exuded by iron bacteria as well as its key role in iron bio-mineralization.Meanwhile,the environmental significance of iron-bacteria/EPS and biogenic iron minerals was also discussed in brief.