Growth and phosphate uptake of microalgae under different phosphate conditions

Sanya Oceanographic Institution (OUC), Ocean University of China, Qingdao, 266100, China

^* Corresponding author: cw1041@stu.ouc.edu.cn

Abstract

Microalgae could utilize the nutrients in the environment and therefore are widely used in wastewater treatment. The variety and complexity of phosphates in the water column and different types of wastewater can affect the growth of microalgae, which further affects the treatment efficiency of phosphorus- containing wastewater. In this study, phosphate uptake and microalgal growth were investigated under different phosphate conditions. The results showed that the increase of phosphate concentration could promote the growth of microalgae. Phosphate species affected the phosphate uptake and transformation process. Orthophosphate and polyphosphate were first adsorbed on the surface of microalgae and then transported inside the cell. Polyphosphates produce desorption in the early stages of uptake. The adsorbed polyphosphates were released back into the culture medium and were taken up and utilized again in the later stages of incubation. Polyphosphates were taken up and utilized by microalgae for a longer period of time than orthophosphates. It was also found that orthophosphate was more readily utilized by microalgae compared to polyphosphate. An increase in phosphate concentration promotes the growth of microalgae.