Isolation and Characterization of Microalgae with potential as human nutrition

Microalgae present significant potential as feedstock for biodiesel production, industrial food applications and pharmacology, along with the production of various high-value products such as pigments and polyunsaturated fatty acids. The selection of strains is essential for maximizing economic feasibility. This study focused on the characterization of two microalgal strains isolated from the Thi Nghe River (Ho Chi Minh City, Vietnam). Phylogenetic analysis of the 18S rDNA-ITS region identified the strains as Desmodesmus armatus and Monoraphidium subclavatum. The primary objectives were to extract and to analyze chlorophyll a, chlorophyll b, carotenoids and phycocyanin from these microalgae. Ultrasound-assisted extraction methods were employed to disrupt the microalgal cells followed by pigment analysis. The results revealed that Monoraphidium subclavatum contained significantly higher levels of pigments compared to Desmodesmus armatus. Specifically, Monoraphidium subclavatum exhibited a higher chlorophyll a content (632.817 ± 12.510 μg/g) than Desmodesmus armatus (268.840 ± 16.024 μg/g). A similar trend was observed for chlorophyll b (364.933 ± 11.801 μg/g in M. subclavatum vs. 162.147 ± 17.562 μg/g in D. armatus) and carotenoids (1899.333 ± 24.007 μg/g in M. subclavatum vs. 180.0 ± 34.044 μg/g in D. armatus). Interestingly, phycocyanin levels were higher in Desmodesmus armatus (0.360 ± 0.010 μg/g) than in Monoraphidium subclavatum (0.247 ± 0.015 μg/g). These findings underscore the potential of these strains for pigment production and biodiesel applications, with M. subclavatum showing particularly promising results in food industry.