Microalgal Cell Biofactory—Therapeutic, Nutraceutical and Functional Food Applications

Abstract

Microalgae are multifaceted photosynthetic microorganisms with emerging business potential. They are present ubiquitously in terrestrial and aquatic environments with rich species diversity and are capable of producing significant biomass. Traditionally, microalgal biomass is being used as food and feed in many countries around the globe. The production of microalgal-based bioactive compounds at an industrial scale through biotechnological interventions is gaining interest more recently. The present review provides a detailed overview of the key algal metabolites, which plays a crucial role in nutraceutical, functional foods, and animal/aquaculture feed industries. Bioactive compounds of microalgae known to exhibit antioxidant, antimicrobial, antitumor, and immunomodulatory effects were comprehensively reviewed. The potential microalgal species and biological extracts against human pathogens were also discussed. Further, current technologies involved in upstream and downstream bioprocessing including cultivation, harvesting, and cell disruption were documented. Establishing microalgae as an alternative supplement would complement the sustainable and environmental requirements in the framework of human health and well-being.

Amphora coffeaeformis diatom involved in reducing the susceptibility of Nile tilapia ( Oreochromis niloticus ) fingerlings to Aeromonas hydrophila infection by boosting immune and antioxidant responses and improving growth performance indicators

“…Recently, microalgae have gained much attention in aquafeeds because they are rich in polyunsaturated fats (PUFAs), proteins, vitamins, pigments and polysaccharide derivatives (Kiran & Venkata Mohan, 2021), in addition to other metabolites that act as immunostimulants, antibacterials and anti‐inflammatories (Lauritano et al, 2016; Ayoub et al, 2019; Ashour et al, 2020; Abdelhamid et al, 2021). A. coffeaeformis , a microalga, contains almost the same amount, or even more of, flavonoids, polyunsaturated fatty acids, sulphated polysaccharides, amino acids, beta (β)‐glucans and antioxidants (alpha (α)‐tocopherol, vitamins C and E) (El‐Sayed et al, 2018).…”

“…Microalgae are ubiquitous unicellular organisms that grow in all aquatic environments (de Morais et al, 2015), and their antimicrobial activity is related to the presence of terpenes, indoles, acetogenins, phenols, volatile halogenated hydrocarbons, and fatty acids (Cardozo et al, 2007). Microalgae are widely used in aquatic animal feed as natural pigments (Di Lena et al, 2019) and as a source of vitamins and polysaccharides (Kiran & Venkata Mohan, 2021). Nile tilapia is one of the most cultured species worldwide, and contributed 65.85% to Egypt's total aquaculture production in 2019 (GAFRD, 2021).…”

Production of microalgae with high lipid content and their potential as sources of nutraceuticals

“…Microalgae serve as a potential source for treating different health conditions and deficiency diseases occurred in populations worldwide. Microalgae can be used for the therapy of cancer, diabetes, hypertension, autoimmune diseases, neurodegenerative diseases and they can also be used for boosting immunity and maintenance of the proper brain and heart health by consuming a sufficient quantity of microalgae per day (Barkia et al 2019 ; Kiran and Venkata Mohan 2021 ; Udayan et al 2021 ). Microalgae have also been used as a moisturizing agent and sun protectants in cosmetics (Udayan et al 2021 ).…”

Paramylon and Other Bioactive Molecules in Micro and Macroalgae

“…Polysaccharides are long-chain polymeric carbohydrates (molecules composed only of carbon, oxygen, and hydrogen) composed of monosaccharide units bound together by glycosidic linkages. Algae contain large amounts of structural polysaccharides (e.g., cellulose, hemicellulose, and lignin), storage polysaccharides (e.g., glucan, fucoidan, agar, carrageenan), and mucopolysaccharides (e.g., porphyran) that the human body and most terrestrial plants are not able to produce [ 10 , 15 , 16 ].…”

“…All of these cultivated algae, as a whole, possess a high-quality nutritional value; hence, they can be considered functional food, i.e., food that beneficially affects one or more target functions in the body. Functional foods provide dietary benefits beyond their macronutrient content and have been recognized to promote excellent health, decrease the risk of mainly non-communicable diseases, such as cardiovascular diseases, cancers, and diabetes, and enhance cost-effective care by promoting a better quality of life [ 10 , 11 ]. Moreover, because of their content in bioactive molecules, such as ω3 essential polyunsaturated fatty acids (PUFAs) (e.g., docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA)), sterols, minerals (e.g., Na, K, Ca, Mg, I), carotenoids (e.g., β-carotene, astaxanthin), essential vitamins (e.g., A, B 1 , B 2 , C, D, E), polyphenols, polysaccharides (e.g., alginate, fucoidan, β-glucan), algae can also be considered a nutraceutical (a crasis of the terms “nutrition” and “pharmaceutical”).…”