Capability of the Microalga Scenedesmus dimorphus for Biodegradation of Crude Oil Components: Biological Responses and Catabolic Intermediates

چکیده مقاله

The capability of Scenedesmus dimorphus for biodegradation of crude oil components is evaluated using biological and biochemical techniques. After exposure of the algal cells to different concentrations of crude oil for 21 day, growth parameters such as cell number as well as fresh and dry weights have increased at low concentrations of crude oil (up to 0.04%) in comparison with control samples. However, growth criteria have decreased in response to the increase in crude oil concentration (0.08%–1%). Similar trends are observed in the content of chlorophylls, carotenoids, flavonoids, anthocyanins, and phenols. Crude oil treatment induces the production of H₂O₂ and thiobarbituric acid reacting substances. Moreover, enhancing crude oil concentration results in increasing activities of superoxide dismutase, polyphenol oxidase, peroxidase, and lipoxygenase. In comparison, the activities of catalase, ascorbate peroxidase, and phenylalanine ammonia lyase increase at low concentrations (up to 0.02%) and then decrease. Using gas chromatography–mass spectrometry analysis several biodegradation intermediate compounds are recognized in the culture media over treatment time. Altogether, S. dimorphus shows considerable potential for biodegradation of crude oil components particularly at concentrations lower than 0.08%. Thus, this microalga can be used as a competent phytoplankton in removal of crude oil from contaminated water supplies.