Isolation of microalgae with potential for integrated biomass production and nutrient removal from wastewater

Abstract The present study firstly investigates the variations of microalgae in the constructed wetland. Then one of the potential microalgal species was isolated and cultured in autotrophic and mixotrophic growth to compare the performance on biomass production and to evaluate the ability of wastewater treatment and simultaneous biodiesel production. Scenedesmus sp. was an abundant strain in the constructed wetland during one year of monitoring. Under both autotrophic and mixotrophic cultivation conditions, an appropriate composition of each source was beneficial for respective biomass production, 8% (v/v) CO2, and 40% piggery wastewater content. The specific growth rate and lipid productivity obtained with autotrophic growth were slightly higher than those obtained by mixotrophic growth. Both cultivation conditions led to dissimilar fatty acid compositions. Comparing the autotrophic and mixotrophic growth, the mixotrophic cultivation not only produced biomass, but also could assimilate up to 81.5% total nitrogen, 64.6% total phosphorus, and 60.7% chemical oxygen demand (COD) from piggery wastewater, respectively. The high biomass productivity was observed at 16.9:1.1:1 of COD/TN/TP of piggery wastewater.