Multifactorial interactions and optimization in biomass harvesting of marine picoalga Picochlorum maculatum MACC3 with different flocculants

Cost effective harvesting of biomass is a major challenge in microalgal industries as it involves the recovery of small sized algal cells from large volumes of culture medium. The present work evaluated the potential of chitosan and aluminium sulfate (AS) in the flocculation of the marine picoalga, Picochlorum maculatum MACC3 using response surface methodology based optimization of flocculation conditions. The viability and integrity of the flocculated cells were assessed using Evan's blue staining and scanning electron microscopy. Under optimized conditions, flocculation efficiency of > 95% was achieved with a chitosan concentration of 63 mg L− 1 at pH 8.5, and aluminium sulfate concentration of 150 mg L− 1 at pH 9.7 with algal biomass concentration of 1.5 g L− 1. Based on flocculation efficiency, cell viability and cell integrity chitosan was selected as an efficient flocculant for biomass harvesting of P. maculatum. The flocculated biomass of this newly isolated nutritionally rich microalga can be further explored for feed applications in aquaculture after accomplishing studies under laboratory and field conditions.