Analysis of Variations in Biomolecules during Various Growth Phases of Freshwater Microalgae Chlorella sp

Chlorella sp. is one of the most studied microalgae because it contains compounds with pharmacological properties, critical to human health. As diversity of the biomolecule changes with the growth of microalgae, it is essential to assess these changes during variou s growth phases for the targeted extraction of biomolecules. In this study, changes in biomolecules extracted from Chlorella sp. at various growth phases were analyzed using various solvent systems.

Chlorella sp. was isolated from a f reshwater pond and three solvents (ethanol, methanol and acetone) were used to extract phyto - compounds from biomasses from three different growth phases (exponential, early stationary and late stationary phases). Analysis of the fatty acids, total phenolic and flavonoid levels, and antioxidant activity were all performed on extracts from different growth phases.

Total flavonoid concentration was highest during the late stationary growth phase in contrary to the early growth stages. In contrast, total phenolic content was highest in the exponential phase. Fatty acid profile revealed that the early growth phases of the algae included higher levels of omega - 3 and omega - 6 polyunsaturated fatty acids in comparison to the late stationary phase. The extract phyto - constituents varied in quantity and type during the microbial growth and were dependent on the solvent system. Correlations between the total phenolic content, fatty acids and DPPH free radical scavenging were positive, demonstrating that the quantity and type of phyto - constituents varied depending on the stages of algal growth. Additional investigations of Chlore lla sp. can develop its potentials for commercial uses.