Effect of phosphorus concentration and light intensity on protein content of microalga Chlorella vulgaris

Abstract

The exploitation of microalgae as a protein source has led to increased interest in the use of microalgae in health food production and source of animal feed. Three light intensities (125, 268 and 300 μEm2sec) and four phosphorous concentrations (0, 2, 4, 6, gl) were used to study their effect on the growth and amount of protein content in Chlorella vulgaris alga. The growth curve of the studied alga was different among the treatments. The stationary phase began at the days 13, 12 and 9 for treatments 125, 268 and 300 (μEm2sec) respectively, while it was identified as day 14, 12, 10 and 6 in treatments 6, 4, 2 and 0 gl of phosphorous respectively. The highest K value was 0.15 at the 268 μEm2sec (control), while the lowest K value was 0.08 at 125 μEm2sec. The shortest doubling time (G) was 2 days at control (268 μEm2sec) treatment.When used different phosphorous concentrations, The highest K value was 0.16 at 0 gl treatment, while the lower K value was 0.1 at 6 gl treatment. The shortest doubling time (G) was 1.8 day in treatment 0 gl.Protein content of C. vulgaris increased from 39.46% to 57.51% at 125 μEm2sec to 300 μEm2sec light intensity. When used different phosphorus concentrations, protein content increased from 51.17% at control treatment (4 gl) to 75.56% at 6 gl treatment.