Improvement in biomass, lipid production and biodiesel properties of a euryhaline Chlorella vulgaris NIOCCV on mixotrophic cultivation in wastewater from a fish processing plant

Abstract

In this study, the changes in biomass productivity, wastewater treatment, lipid production and biodiesel properties from mixotrophic cultivation of Chlorella vulgaris NIOCCV in untreated wastewater from a fish processing plant over F/2 medium was reported. A significant 6-fold increase in biomass productivity (257.87 ± 1.27 mg·L−1·d−1) and 1.3-fold in lipid accumulation (48%) was recorded for C. vulgaris NIOCCV cultivated in wastewater enrichment of 15% (v/v) over F/2 medium. The biomass productivity was significantly higher in wastewater enrichment up to 50% (v/v) and salt concentration 5% (w/v) than in F/2 medium. The fatty acid methyl esters based theoretical calculation for biodiesel properties from the microalgal biomass cultivated in wastewater enriched medium were found superior to the same from the F/2 medium. The resultant biodiesel properties (CN value, oxidation stability, and kinematic viscosity) were in compliance to both the ASTM D6751 and EN 14214 fuel standards. The cultivation of C. vulgaris NIOCCV in wastewater resulted in significant decrease in nutrient levels is another advantage. Therefore, C. vulgaris NIOCCV can effectively be cultivated in untreated fish processing industry wastewater without addition of nutrients. Further, C. vulgaris NIOCCV can efficiently be utilized as bioresource for biodiesel production.