Exploring of the Green Algae Chlorella Vulgaris Potential for Phenantherene Biodegredation

Abstract

The distribution of polycyclic aromatic hydrocarbons (PAHs) as a group of toxic, and persistent aromatic pollutants in the environment is rapidly enhancing. These compounds have adverse impacts on the health of living organisms. It is necessary to find an effective method for the elimination of PAHs from the ecosystems.  In the last decades, phycoremediation as an effective, low-cost and ecofriendly technology for the cleanup of different pollutants has gained a great attention. Hence, the present study has been focused on potential of the green microalga Chlorella vulgaris for degradation of phenanthrene as a toxic 3-ring PAHs. The impact of the phenanthrene on Chlorella vulgaris cells was evaluated by assay of alga growth, protein assay and GC–MS analysis. Four different concentrations (2, 10, 25 and 50 mg L^-1) of phenanthrene were selected for the study. Intriguingly, optical density, as a growth factor of algae, was enhanced when treated with 2 mg L^-1 of phenanthrene after 7 days exposure in comparison to control. The cellular growth and total protein content were decreased as the concentration of phenanthrene increased from 10 to 50 mg L^-1 at the same exposure. Furthermore, GC/MS technique explained the biological degradation of phenanthrene in the present research and accordingly, a number of intermediate by-products were identified. The obtained results confirmed that phenanthrene is able to induce cytotoxicity in Chlorella cells in high concentrations and subsequently Chlorella vulgaris has noticeable potential in its biodegradation.