Jiangsu Provincial Key Laboratory of Marine Biology, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China.
Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base, Ministry of Science and Technology, Nanjing, 210014, China.
Bull Environ Contam Toxicol. 2020 Dec;105(6):868-873. doi: 10.1007/s00128-020-03045-y. Epub 2020 Nov 19.
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 at 72 h of culture). The As(V) percentage in the P-enriched (11.2 mg L) 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.
砷（As）污染是一个众所周知的全球性环境问题，存在于陆地和水生环境中。亚砷酸盐 [As(III)] 的生物氧化和随后的砷酸盐 [As(V)] 去除，越来越多地被用于受污染地下水的修复。然而，对于微藻，尤其是来自咸水环境的微藻对砷（III）的氧化作用，人们知之甚少。在这项研究中，我们研究了不同磷酸盐浓度存在下，海洋微藻杜氏盐藻中砷（III）的毒性和氧化作用。砷（III）毒性实验的结果表明，杜氏盐藻能够耐受砷（III）（培养 72 小时时 5.4±0.31 mg As L）。在 24 小时暴露后，富磷（11.2 mg L）培养基中的砷（V）百分比比缺磷培养基中的高 7.2 倍，这表明随着磷酸盐水平的升高，杜氏盐藻对砷（III）的氧化作用更为明显。用和不用 2,4-二硝基苯酚（DNP）处理藻类细胞表明，砷（III）的氧化主要发生在杜氏盐藻的细胞表面和细胞质中。本研究结果表明，将砷（III）转化为砷（V）可能是杜氏盐藻解毒的一个重要途径，而磷酸盐在这一氧化过程中起着关键作用。
