Effects of Different Phosphorus Concentrations on Biomass and Growth in Green Microalgae Chlorococcum sp

A large number of factors affects in the rise and fall of biomass and growth in microalgae populations. One of the most important factors is phosphorus (orthophosphate) in microalgae culture medium. In this study, effects of six treatments including; BBM (Bold’s Basal Medium) as control, BBM+soil extract, BBM+5, 10, 15, and 25 mg/L of Na3PO4.12H20 each as one treatment on dry biomass, growth and chlorophyll a of Chlorococcum sp. were investigated in completely randomize design with three replicates under laboratory conditions. Results showed that the maximum algal densities were peaked on 10-day culture with BBM+ 25 (11.04×106 cells/mL) and BBM+soil extract (11.54×106 cells/mL). In addition, the mean highest dry biomasses were obtained 0.792 and 0.773 mg/mL at BBM+soil extract and BBM+25, respectively. Results showed that the highest mean chlorophyll a was at BBM+ 25 (11.39 mg/L) and BBM+soil extract (11.20 mg/L). The mean maximum specific growth rate (SGR) and minimum doubling time (Dt) were obtained from BBM+ soil extract (0.128 /dayand 5.43 days) and BBM+25(0.124 /day and 5.60 days).