Microalgae: A Promising Source of Valuable Bioproducts

Abstract

Microalgae are a group of autotrophic microorganisms that live in marine, freshwater and soil ecosystems and produce organic substances in the process of photosynthesis. Due to their high metabolic flexibility, adaptation to various cultivation conditions as well as the possibility of rapid growth, the number of studies on their use as a source of biologically valuable products is growing rapidly. Currently, integrated technologies for the cultivation of microalgae aiming to isolate various biologically active substances from biomass to increase the profitability of algae production are being sought. To implement this kind of development, the high productivity of industrial cultivation systems must be accompanied by the ability to control the biosynthesis of biologically valuable compounds in conditions of intensive culture growth. The review considers the main factors (temperature, pH, component composition, etc.) that affect the biomass growth process and the biologically active substance synthesis in microalgae. The advantages and disadvantages of existing cultivation methods are outlined. An analysis of various methods for the isolation and overproduction of the main biologically active substances of microalgae (proteins, lipids, polysaccharides, pigments and vitamins) is presented and new technologies and approaches aimed at using microalgae as promising ingredients in value-added products are considered.

Production, Purification, and Study of the Amino Acid Composition of Microalgae Proteins

“…It has been reported that some microalgae contain soluble proteins in their cytoplasm [ 3 , 4 ]. In addition, microalgae with chloroplasts contain soluble protein, central pyrenoid, and phytobiliproteins, although some microalgae, such as Arthrospira platensis , instead, have thylakoid sacs surrounding the peripheral cytoplasm associated with phycobilisomes [ 5 , 6 ].…”

Comparison of growth, protein and carotenoid contents of some freshwater microalgae and the effects of urea and cultivation in a photobioreactor with reflective broth circulation guide on Desmodesmus subspicatus LC172266

“…Protein is another important product of microalgae used as food/feed supplements. The protein content of microalgae varies from 30 to70% of dry weight depending on the species of microalgae as well as the culture conditions (Ejike et al 2017 ; Dolganyuk et al 2020 ). The concentration of nitrogen in the nutrient medium is known to affect protein accumulation in microalgae species.…”

Study of Morphological Features and Determination of the Fatty Acid Composition of the Microalgae Lipid Complex

“…Analysis of the sequences of the 16S rRNA and 18S rRNA genes ( Appendix A , Appendix B and Appendix C ) made it possible to conclude that they fully corresponded to the genotypes of the microalgae Chlorella vulgaris , Arthrospira platensis , and Dunaliella salina . Since they are typical microalgae of the Baltic Sea and water bodies of the Kaliningrad region (Russia), their lipid potential was studied as a possible raw material basis for feed and dietary supplements [ 3 ].…”

“…Microalgae cultivation is attracting more research due to its ability to synthesize various biologically active substances, the rapid growth of biomass, and the possibility of adjusting their biochemical composition depending on the cultivation conditions [ 1 , 2 , 3 ]. Unlike heterotrophic microorganisms, which require various organic compounds for growth, single-celled photosynthetic organisms produce biomass from fully oxidized inorganic substances and mineral elements due to light energy converted during photosynthesis [ 4 ].…”