Removal and biodegradation of polycyclic aromatic hydrocarbons by Selenastrum capricornutum
Removal and biodegradation of polycyclic aromatic hydrocarbons by Selenastrum capricornutum
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DOI：
10.1897/05-354r.1
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发表时间：
2006-07-01
影响因子：
4.1
通讯作者：
Tam, Nora Fung Yee
中科院分区：
文献类型：
--
作者：
Chan, Sidney Man Ngai;Luan, Tiangang;Tam, Nora Fung Yee
研究了一种绿色微藻羊角月牙藻（Selenastrum capricornutum）在不同初始细胞密度下对菲（PHE）、荧蒽（弗拉）和芘（PYR）等多环芳烃（PAHs）混合物的去除和降解。随着初始细胞密度的增加，对PAH的去除率逐渐提高，培养液中PHE、弗拉和PYR的去除率分别为96%、100%和100%。在1 × 10 ~（7）cells/ml的细胞密度下，4d时对多环芳烃的去除率最高，而在最低细胞密度（5 × 10 ~（4）cells/ml）下，7 d时去除率低于50%。去除机制包括初始吸附到活细胞和死细胞的细胞壁上，然后吸附的多环芳烃被吸收和降解的活细胞。在混合体系中，不同浓度的多环芳烃，无论是相同浓度还是不同浓度，活菌S.羊角藻的降解速率为PYR >弗拉> PHE，而弗拉> PYR > PHE。PAH代谢产物的初步研究结果表明，PHE被转化为四种不同的单羟基菲和两种二羟基菲，而弗拉和PYR通过单加氧酶途径转化为三种羟基化衍生物。二羟基化多环芳烃的存在表明双加氧酶途径也可能同时发生。
The removal and degradation of a mixture of polycyclic aromatic hydrocarbons (PAHs), namely phenanthrene (PHE), fluoranthene (FLA), and pyrene (PYR), by a green microalgal species, Selenastrum capricornutum, at different initial cell densities were studied. The PAH removal efficiency increased with the initial cell density, and 96% of PHE, 100% of FLA, and 100% of PYR in the medium were removed by live S. capricornutum at the density of I X 10(7) cells/ml in 4 d, whereas less than 50% of PAHs were removed at the lowest cell density (5 X 10(4) cells/ml) in 7 d. The removal mechanisms included initial adsorption onto the cell walls of both live and dead cells, and the adsorbed PAHs were then absorbed and degraded in live cells only. Among different PAHs in a mixture, irrespective of whether they were added to medium at the same or different concentrations, the removal preference by live S. capricornutum was in the descending order of PYR > FLA > PHE, whereas the biodegradation rates followed the descending order of FLA > PYR > PHE. Initial findings regarding PAH metabolites revealed that PHE was converted into four different monohydroxyphenanthrenes and two dihydroxyphenanthrenes, whereas FLA and PYR were converted into three hydroxylated derivatives through the monooxygenase pathway. The presence of dihydroxylated PAHs suggested that the dioxygenase pathway also might have taken place at the same time.