Effect of different phosphorus concentrations on the growth rate and biochemical composition of Isochrysis galbana

Phosphorus one of the critical macronutrient that plays an important role in energy transfer, phospholipid and nucleic acids synthesis and biochemical compounds in microalgae cells, as well as plays an important role in the formation and transfer of metabolic energy in ATP and NADP. In this study, the effect of different phosphorus concentration (0, 2, 4, 8 and 16 mg/L) on growth rate and biochemical composition of Isochrysis galbana was investigated. The results showed phosphorus deprivation decreased cell growth, pigments and protein; while carbohydrate and lipid content of I. galbana increased as the phosphorus concentration increased. The highest carbohydrate, protein and lipid content were 23.5, 34.6 and 36.2 % in phosphorus concentrations of 0, 8, 0 mg/L, respectively. Also, by increasing the concentration of phosphorus from 0 to 16 mg/l, the content of C16: 0 (33.96%) and C18: 0 (23.4%) decreased to 27.75% and 14.37%, respectively. The results of this study indicate that phosphorus concentration significantly affects the growth rate and biochemical compositions of I. galbana.