The comprehensive impact of phosphorus sources on microalgae biochemical metabolism and phosphorus transformation

Understanding the comprehensive impact of phosphorus sources on microalgae growth process is an essential precondition for microalgae cultivation. In this study, the combination of inorganic phosphorus (K2HPO4 and Na5P3O10) and organic phosphorus (ATP and G6P) on microalgae biochemical metabolism and phosphorus transformation with wastewater was clarified. Both inorganic phosphorus (IP) and organic phosphorus (OP) could be absorbed and utilized by Chlorella pyrenoidosa under mixotrophic condition. The maximum dry cell weight was obtained with K2HPO4 and ATP at an IP/OP proportion of 1:3, which was 1.04, 1.09 and 1.30 times higher than K2HPO4 and G6P, Na5P3O10 and ATP, Na5P3O10 and G6P, respectively. The increasing proportion of OP was advantageous for microalgae growth, but disadvantageous for lipid accumulation. Besides, the intracellular phosphorus was classified and quantified by 31P NMR spectroscopy to ascertain its metabolism and transformation. Results provided a fresh perspective on the utilization of complex phosphorus sources with microalgae.