Chromate tolerance and accumulation in Chlorella vulgaris L.: Role of antioxidant enzymes and biochemical changes in detoxification of metals

A concentration-dependent increase in activity of antioxidant enzymes (catalase, ascorbate peroxidase, glutathione, superoxide dismutase) and carotenoid, MDA level have been observed in the green alga Chlorella vulgaris following chromium exposure at different concentrations (0.01-100 μg ml−1). Simultaneously, decrease in growth rate, chlorophyll and protein contents was observed. In case of ascorbate peroxidase, glutathione peroxidase and superoxide dismutase a bell shaped dose response was evident, however, lipid peroxidation followed a linear relationship along with catalase activity, which could be used as biomarker of Cr toxicity and played important role in providing tolerance and subsequently, high accumulation potential of chromium in C. vulgaris. In present investigation, the green alga C. vulgaris respond better under chromium stress in terms of tolerance, growth and metal accumulating potential at higher concentration of Cr (VI) which could be employed in decontamination of chromium for environmental cleanup.