THE INFLUENCE OF DIFFERENT PHOSPHATE AND NITRATE CONCENTRATIONS ON GROWTH, PROTEIN AND CHLOROPHYLL A CONTENT OF Scenedesmus obliquus

Abstract

The growth, chlorophyll a and protein production with Scenedesmus obliquus was performed in modified Johnson's medium at initial phosphorus and nitrogen concentrations of 0.1, 0.3, 0.5, 0.7 (P) and 8, 12, 16 20 mM (N). Initial concentrations of both nutrients had a significant effect (p>0.01) on growth and contents. The highest yield (15.5 +/- 0.176 x 10(6) cell mL(-1)), chlorophyll a (10.3 +/- 0.157 mg L(-1)), and protein yields (32.3 +/- 0.323 ma L(-1)) were obtained with concentrations of 0.3 mM phosphate and 12 mM nitrate. Cell number showed significant correlations with amount of chlorophyll a (p<0.01, r = 0.97) and protein (p<0.01, r = 0.83). The medium with a 40:1 N/P ratio favored S. obliquus growth. Specific growth rates varied from 0.28 to 0.40 cell divisions d(-1).