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Abstract

Background and Objective Reactive oxygen species ROS are produced due to imbalance between cellular ROS production and elimination leading to oxidative stress. Antioxidants are known to involve in protecting cells from oxidative stress induced by various stresses in micro-algae. This study was carried out with the objective of determining the antioxidant system responses in micro-algae grown under nutrient stress conditions. Materials and Methods Chlorococcopsis minuta was cultivated in nitrogen and phosphorous reprieve and deprived conditions and enzymatic superoxide dismutase, catalase, ascorbate peroxidase and non-enzymatic Hydrogen peroxide, proline, polyphenol content and lipid per-oxidation level antioxidants were analyzed. Results Activities of antioxidant enzymes in C. minuta during nutrient stress showed that the activities of SOD, CAT and APX were increased in nutrient stress cultures when compared to nutrient fulfilled conditions. There was a 33 increase in lipid per-oxidation N-P- media than N-P media. Proline content increased with nutrient stress and reached 8 folds higher in nitrogen and phosphorous deprived media than the control. Total phenolic content was greater in N-P- indicating the nutrient stress triggered antioxidant system in the micro-algae. Conclusion Nitrogen deprivation with phosphorous depletion condition demonstrated the oxidative stress and enhanced activation of enzymatic and non-enzymatic antioxidant systems at various levels.