Microalgae Cultivation and Harvesting

Abstract

In this research, we tried to use mixotrophic condition to study the effect of dissolved oxygen, pH, aeration, and organic carbon in the microalgal growth process, and try to find the effective harvesting methods. We realized that using acetate as additional carbon resources can enhance microalgal growth rate dramatically when we input ammonia acetate in the culture medium under automated pH controlling by using CO2, the DO value was dropped to almost 0, at the same time the growth rate will arrive at the maximum 0.936 g L-1 d-1. Whereas, the other groups showed the much lower growth rate, blank (0.017 g L-1 d-1), DO controlling( 0.019 g L-1 d-1), aeration(0.127 g L-1 d-1), pH control(0.102 g L-1 d-1), aeration with pH controlling with acetate (0.662 g L-1 d-1). From this fact, we conclude that using ammonia acetate can create the anoxic condition which can stimulate microalgae growth dramatically, but only removing dissolved oxygen by using N2 has little impact on microalgae growth. Besides, in the microalgae harvesting tests, the PGA can be effective coagulator in microalgae harvesting processes. And with the solution cell concentration increased, the harvesting efficiency increased quickly at begining and keeps stable after the initial biomass concentration is more than 0.8 g/L