产嗜铁素砷抗性微生物在砷污染环境中的作用

Role of siderophore-producing and arsenic-resistant bacteria in arsenic-contaminated environment

摘要:

在砷污染环境中，许多微生物进化出了砷抗性，对地球环境中砷的命运起着决定性的作用。其次，由于自然条件下铁有效浓度低，微生物一般会表达嗜铁素，协助微生物吸收铁。嗜铁素除了与铁结合外，还可与多种金属离子形成稳定的复合物，促进环境中砷酸盐的溶解和亚砷酸盐的氧化。最后，产嗜铁素微生物有促进植物生长和促进或减弱植物吸收砷的可能性。因此，产嗜铁素砷抗性微生物可能具有在砷污染环境的修复中发挥作用的潜力。

Abstract:

Arsenic-resistant microorganisms are abundant in surface and near-surface arsenic-contaminated environment, substantially affecting the fate and transport of arsenic in the environment. Siderophores produced by microorganisms under iron-limiting conditions have high affinity for ferric iron and enhance the uptake of iron to the microorganisms. Siderophores help sequester Fe, which is needed to activate AsIII oxidase as Fe is unavailable at physiological pH. Although the principal role of siderophores is to chelate ferric iron, they can also chelate wide array of toxic metals. Inoculation of plants with siderophore-producing bacteria has been found to either promote or reduce heavy metal uptake. Therefore, the siderophore-producing and arsenic-resistant bacteria might have the potential in the remediation of arsenic contamination environment.