Removal and biodegradation of polycyclic aromatic hydrocarbons by Selenastrum capricornutum

Sidney Man Ngai Chan, Tiangang Luan, Ming Hung WONG, Nora Fung Yee Tam*

*Corresponding author for this work

Research output: Contribution to journalJournal articlepeer-review

151 Citations (Scopus)


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 1 × 10 7 cells/ml in 4 d, whereas less than 50% of PAHs were removed at the lowest cell density (5 × 104 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.

Original languageEnglish
Pages (from-to)1772-1779
Number of pages8
JournalEnvironmental Toxicology and Chemistry
Issue number7
Publication statusPublished - Jul 2006

Scopus Subject Areas

  • Environmental Chemistry
  • Health, Toxicology and Mutagenesis

User-Defined Keywords

  • Fluoranthene
  • Monooxygenase
  • Phenanthrene
  • Pyrene
  • Selenastrum capricornutum


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