摘要:
砷是一种广泛存在于环境中的有毒物质。集胞藻属于单细胞藻类,广泛分布在淡水生态环境中。采用营养液培养的方法探讨了集胞藻(Synechocystis sp.PCC6803)对砷的累积和转化特性。当集胞藻分别暴露于2和100 μM的无机As (Ⅲ)和As (V)14 d后,体内的砷形态均以As (V)为主,并且在100 μM浓度处理下检测到DMA,结果表明集胞藻体内存在砷的氧化和还原机制,只有高浓度砷才能诱导集胞藻体内的砷甲基化机制起作用。研究了集胞藻在含磷培养基中对不同形态砷的吸收动力学特征,As (Ⅲ)的最大吸收速率大于As (V)的最大吸收速率,而集胞藻对As (V)的亲和性大于As (Ⅲ)。考察了集胞藻对含砷溶液的净化作用,72 h集胞藻净化效率能达到41%,此结果表明集胞藻具有修复砷污染水体的潜力。
Abstract:
Arsenic (As) is a highly toxic and widespread environmental contaninant. Synechocystics belongs to unicallular algae which is widely distributed in fresh-water. Synechocystis sp. PCC6803 cultivated in medium was exposed to arsenite and arsenate in order to investigate uptake, accumulation and transformation of arsenic species in Synechocystis. After exposed to both arsenite (2 μM) and arsenate (100 μM) 14 days, As(V) was the main species in Synechocystis. DMA was detected in Synechocystis treated with arsenate at 100 μM. The result showed that mechanisms of arsenic reduction and oxidation were present in Synechocystis simultaneously, and mechanisms of arsenic methylation only can be induced at high concentration of arsenate. The kinetics of arsenite and arsenate uptake of Synechocystise showed that the the uptake rate of As(Ⅲ) was faster than that of As(V), while the affinity of As(V) was higher than that of As(Ⅲ) in Synechocystis. Purification effect of Synechocystis for arsenic solution was studied as well. Purification efficiency of Synechocystis can reach 41% in 72 hours, that clarified Synechocystis have the ability to repair arsenic pollution water.
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