Microalgal competence in urban wastewater management: phycoremediation and lipid production

Abstract

The present study was conducted to assess the strain aptness, phycoremediation potential and lipid yield in microalgae <i>Chloroccocum humicola</i> and <i>Oscillatoria</i> sp. Results revealed that microalgae treated with different concentration of wastewater (25%, 50%, 75% and 100%) recovered nutrients (Nitrogen: 50.55-85.90%, Phosphorus: 69.98-93.72%) and removed heavy metals (24.17-88.10%) from wastewater. Microalgae <i>C. humicola</i> showed significant reduction in physico-chemical parameters of wastewater at 25% and 50% respectively with considerable increase in lipid production (1.61 folds) at 50% wastewater concentration. In order to counterbalance the wastewater induced toxicity, both microalgae exhibited stimulated antioxidants viz., proline (1.26-4.04 folds), ascorbic acid (1.01-9.21 folds), cysteine (1.44-4.92 folds), catalase (0.99-3.63 folds), superoxide dismutase (1.15-1.43 folds) and glutathione reductase (1.43-6.67 folds) at different wastewater concentrations. Further, Fourier transforms infrared spectroscopy spectral elucidation of <i>Chloroccocum humicola</i> at 50% reflected high lipid peak in the regions 3000-2800<b> </b>cm^-1 as compared to <i>Oscillatoria</i> sp. Thus, growth characteristics, biochemical responses and lipid yield presented the suitability of the <i>Chloroccocum humicola</i> to be used in phycoremedation, resource recovery as well as lipid production, which may be further utilized as potent feedstock for third generation energy demand.