Biochemical composition and bioactivity screening of various extracts from Dunaliella salina, a green microalga.

The current study examines the antimicrobial and antioxidant properties of different extracts of the microalga Dunaliella salina Teodoresco (Dunaliellaceae), their fatty acid composition and the antimicrobial activity of the oil. Antimicrobial and antioxidant activities were evaluated by obtaining extracts of D. salina in n-hexane, dichloromethane, ethanol, and methanol. To evaluate the antimicrobial activity, the extracts, and fatty acids from D. salina were assessed by the disc diffusion and microdilution techniques against pathogenic microorganisms including fish and clinical/food-borne. The MBC or MFC values of the extracts and fatty acids ranged from 0.63 to 10.00 mg/ml. The antioxidant activity was studied by phosphomolybdenum and DPPH assays and ß-carotene/linoleic acid tests. In addition, the total phenolic and flavonoid contents were evaluated and the fatty acid composition was determined using gas chromatography. Palmitic, alpha-linolenic, and oleic acids were discovered to be the major components of the fatty acids. These findings have demonstrated that the extracts and oil from D. salina could be used as natural antimicrobials and antioxidants in the food/feed and pharmaceutical industry and as a biodiesel because of its high unsaturated fatty acid content.