Not only they can convert energy but they also used to produce high-value compounds. Spray-dried microalgal biomasses typically contain 3–7 % moisture, 46–63 % protein, 8–17 % carbohydrates, 4–22 % lipids, 2–4 % nucleic acid, 7–10 % ash, and a wide range of vitamins and other biologically active substances such as bioactive peptides and pigments. Microalgae have been commercially produced, and the mainly used genera are Chlorella and Arthrospira for health food.