Arsenic (As) contamination in terrestrial and aquatic environments is a well-known global environmental problem. The biooxidation of arsenite [As(III)] and subsequent arsenate [As(V)] removal have increasingly been used for remediation of As-polluted groundwater. However, little is known about As(III) oxidation by microalgae, especially those from saltwater environments. In this study, we investigated As(III) toxicity and oxidation in the marine microalga Dunaliella salina in the presence of different phosphate concentrations. The results of the As(III) toxicity experiments showed that D. salina was tolerant to As(III) (5.4 ± 0.31 mg As L⁻¹ at 72 h of culture). The As(V) percentage in the P-enriched (11.2 mg L⁻¹) medium was 7.2-fold greater than in the P-deficient one after 24-h exposure, indicating As(III) oxidation by D. salina was more pronounced with increased phosphate levels. Treatment of As(III) with and without 2,4-dinitrophenol (DNP) on the algal cells showed that As(III) oxidation occurred mainly on the cell surface and in the cytoplasm of D. salina. The results of this study suggest that transformation of As(III) into As(V) may be an important pathway of detoxification in D. salina and that phosphate plays a key role in this oxidation process.

陆地和水生环境中的砷污染是一个众所周知的全球环境问题。砷[As（III）]的生物氧化和随后的砷酸盐[As（V）]去除已越来越多地用于修复As污染的地下水。然而，关于微藻类氧化As（III）的知之甚少，特别是来自盐水环境的氧化。在这项研究中，我们研究了在不同磷酸盐浓度下海洋微藻杜氏盐藻中的As（III）毒性和氧化作用。As（III）毒性实验的结果表明，盐假丝酵母可耐受As（III）（培养72 h时为5.4±0.31 mg As L ^-1）。富P（11.2 mg L ^-1）中的As（V）百分比）暴露24小时后，培养基比缺乏P的培养基高7.2倍，这表明盐藻D.盐沼的As（III）氧化随着磷酸盐含量的增加而更加明显。在藻类细胞上添加和不添加2,4-二硝基苯酚（DNP）处理As（III）表明，As（III）氧化主要发生在盐藻中细胞表面和细胞质中。这项研究的结果表明，砷（III）转化为砷（V）可能是盐藻中解毒的重要途径，磷酸盐在该氧化过程中起关键作用。