Phycoremediation resultant lipid production and antioxidant changes in green microalgae Chlorella Sp.

ABSTRACT

In this investigation, we report on the treatment of tannery wastewater using microalgae Chlorella species to produce lipid and fatty acid as well as changes in antioxidant metabolism during the treatment. The variation in growth, production of pigments, antioxidant metabolism, lipid and fatty acids, and nutrient removal from wastewater during the remediation were observed. Surprisingly, a profuse growth was found in 50% diluted tannery wastewater (TW), which supported to accumulate high yield of lipid (18.5%) and unsaturated fatty acids (50.05%). The antioxidant activity of microalgae in both the concentrations (50% and 100% TW) were viz., lipid peroxidation 1.6 ± 0.1 and 2.3 ± 0.02nmol MDA mg⁻¹ protein, SOD 10.3 ± 0.4 and 15.7 ± 0.9 U mg⁻¹ protein, CAT 0.17 ± 0.036 and 0.52 ± 0.06 U mg⁻¹ protein, and APX 7.2 ± 0.8 and 11.2 ± 09 U mg⁻¹ protein respectively, which point out that the free radical scavenging mechanism against heavy metal stress. Maximum phycoremediation of heavy metals observed from both concentrations during the healthy growth period were Cr – 73.1, 45.7%, Cu – 90.4, 78.1%, Pb – 92.1, 52.2%, and Zn – 81.2, 44.6%, respectively. This study proved the potential use of Chlorella for heavy metal and nutrient removal from tannery wastewater. Moreover, an unaffected growth with high antioxidant activity of this species promises a sustainable lipid and fatty acid contents for biofuel production.

KEYWORDS:

• antioxidants
• Chlorella
• fatty acids
• lipid
• phycoremediation
• tannery

Acknowledgments

The first author expresses his sincere thanks to DST (Department of Science and Technology), SERB (Science and Engineering Research Board) – Fast Track Young Scientist Scheme (File No.YSS/2014/000206), New Delhi for the financial support. Authors are also thankful to Unnikannan P, Department of Botany, Annamalai University for tannery effluent.

Additional information

Funding

Department of Science and Technology (DST), Science and Engineering Research Board (SERB)- Fast Track Young Scientist Scheme (File No. YSS/2014/000206), New Delhi, India.