Abstract

CALDERON-DELGADO, Ivonne C.; MORA-SOLARTE, Diego A.  and  VELASCO-SANTAMARIA, Yohana M.. Physiological responses and antioxidant capacity of Chlorella vulgaris (Chlorellaceae) exposed to Phenanthrene. Acta biol.Colomb. [online]. 2020, vol.25, n.2, pp.225-234. ISSN 0120-548X.  https://doi.org/10.15446/abc.v25n2.77783.

Aromatic hydrocarbons have a high toxicological potential; therefore, their evaluation in aquatic organisms has great importance. The microalgae C. vulgaris was selected because it is one of the most dominant algae species in water and due to its potential to degrade or absorb different xenobiotics. The objective was to evaluate the toxicity in C. vulgaris exposed to phenanthrene (PHE), evaluating physiological parameters such as cell density, the content of chlorophyll a and chlorophyll b and enzymatic activity of superoxide dismutase (SOD) and catalase (CAT) to define short-term toxic responses. Five different concentrations (0.1; 1.0; 10; 100 and 1000 µg PHE. L-1), a solvent control treatment (acetone) and control (without additives) were evaluated for seven days. A dose-dependent behaviour was observed in all physiological responses, decreasing progressively with the increase in PHE concentrations. Cell density, growth rate, cell diameter, and chlorophyll can be considered biomarkers of toxicity. The activity of CAT and SOD in C. vulgaris decreased considerably during the entire study period, possibly due to excessive production of reactive oxygen species generated by exposure to phenanthrene causing the inhibition of these antioxidant enzymes. Despite the evident toxicity of this hydrocarbon observed in this study, C. vulgaris presents a high resistance and adaptation to this contaminant, so it is possible to infer that this microorganism can show toxicological effects in an environment with this contaminant in a short period.

Keywords : Antioxidant; growth inhibition; microalgae; polycyclic aromatic hydrocarbon; toxicity.

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