Exploring economic viable species via assessing a tropic-specific microalgal collection

Locations around the equator provide unique habitats for microalgae presumably with exceptional vitality. To develop microalga-derived product systems, we previously created a (sub)tropical microalgal collection. In this study, two Chlorella strains (MEM176 and MEM193), adaptive to typical tropical climate, were isolated from the collection. The production performance was evaluated where both strains showed a robust growth in high temperatures and light intensities. Specifically, the strains MEM176 and MEM193 produced 503.6-mg/(L·d) and 411.3-mg/(L·d) biomass, respectively, with high contents of proteins. Their commercial and nutritional values were emphasized by amino acid compositions (e.g., proline, valine, and phenylalanine). Particularly, higher amounts of proline were revealed in MEM176 (47.9 mg/g dry biomass (DW)) and MEM193 (47.9 and 59.2 mg/g DW) than available commercial strains. Compared with MEM193, MEM176 produced 129.7% more lipids in which unsaturated fatty acids (particularly linoleic acid and α-linolenic acid) account for 65% of the total lipids. Therefore, it is promising to explore the potential of these Chlorella strains as food additives via outdoor cultivation in tropical area, notably MEM176 that exhibits superiority as sources of essential amino acids and valuable fatty acids.