Removal and biodegradation of polycyclic aromatic hydrocarbons by Selenastrum capricornutum.

Environ Toxicol Chem

Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, People's Republic of China.

Published: July 2006

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 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.

Download full-text PDF

Source
http://dx.doi.org/10.1897/05-354r.1DOI Listing

Publication Analysis

Top Keywords

polycyclic aromatic
8
aromatic hydrocarbons
8
selenastrum capricornutum
8
initial cell
8
cell density
8
live capricornutum
8
descending order
8
fla pyr
8
removal
5
pahs
5

Similar Publications

Acenes are an important class of polycyclic aromatic hydrocarbons that have gained considerable attention from chemists, physicists, and material scientists, due to their exceptional potential for organic electronics. They serve as an ideal platform for studying the physical and chemical properties of sp carbon frameworks in the one-dimensional limit and also provide a fertile playground to explore magnetism in graphenic nanostructures due to their zigzag edge topology. While higher acenes up to tridecacene have been successfully generated by means of on-surface synthesis, it is imperative to extend their synthesis toward even longer homologues to comprehensively understand the evolution of their electronic ground state.

View Article and Find Full Text PDF

Increased industrial offshore activities in northern waters raise the question of impact of polycyclic aromatic hydrocarbons (PAHs) on key Arctic marine species. One of these is the ecologically important polar cod (Boreogadus saida), which is the primary food source for Arctic marine mammals and seabirds. In the present work, we have conducted the first comprehensive proteomics study with this species by exploring the effects of dietary PAH exposure on the hepatic proteome, using benzo[a]pyrene (BaP) as a PAH model-compound.

View Article and Find Full Text PDF

Unveiling emerging polycyclic aromatic compounds in the urban atmospheric particulate matter.

Environ Int

January 2025

State Key Laboratory of Marine Pollution and Department of Chemistry, City University of Hong Kong, Hong Kong 999077, China; Department of Applied Science, School of Science and Technology, Hong Kong Metropolitan University, Hong Kong 999077, China.

Despite the ubiquity and complexity of atmospheric polycyclic aromatic compounds (PACs), many of these compounds are largely unknown and lack sufficient toxicity data for comprehensive risk assessments. In this study, nontarget screening assisted by in-house and self-developed spectra databases was, therefore, employed to identify PACs in atmospheric particulate matter collected from multiple outdoor settings. Additionally, absorption, distribution, metabolism, excretion, and toxicity properties were evaluated to indicate PAC's overall abilities to cause adverse outcomes and incorporated into a novel health risk assessment model to assess their inhalation risks.

View Article and Find Full Text PDF

Despite being studied for almost two centuries, aromaticity has always been a controversial concept. We previously proposed a unified aromatic rule for π-conjugated systems by two-dimensional (2D) superatomic-molecule theory, where benzenoid rings are treated as period 2 2D superatoms (3π-N, 4π-O, 5π-F, 6π-Ne) and, further, bond to form 2D superatomic molecules. Herein, to build a 2D periodic table, we further extend the theory to period 3 (7π-P, 8π-S, 9π-Cl, 10π-Ar) and period 1 (1π-H, 2π-He) elements.

View Article and Find Full Text PDF

Selective and Divergent Synthesis of Naphthalene- and Phenanthrene-Fused Azahelicenes by Turning Rearrangement On or Off.

Chemistry

January 2025

Okayama Daigaku Daigakuin Shizen Kagaku Kenkyuka, Division of Applied Chemistry, JAPAN.

The Scholl reaction has been used to synthesize a variety of polycyclic aromatic hydrocarbons, where 1,2-aryl shifts have sometimes occurred to yield unique rearrangement products. However, such 1,2-aryl shifts are often uncontrollable, and the selective and divergent synthesis with or without rearrangement is desired. Here, we achieved the control of the rearrangement in the Scholl reaction of carbazoles by the N-substituents.

View Article and Find Full Text PDF

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!