Microalgae as Sustainable Biofactories to Produce High-Value Lipids: Biodiversity, Exploitation, and Biotechnological Applications

Abstract

Microalgae are often called “sustainable biofactories” due to their dual potential to mitigate atmospheric carbon dioxide and produce a great diversity of high-value compounds. Nevertheless, the successful exploitation of microalgae as biofactories for industrial scale is dependent on choosing the right microalga and optimum growth conditions. Due to the rich biodiversity of microalgae, a screening pipeline should be developed to perform microalgal strain selection exploring their growth, robustness, and metabolite production. Current prospects in microalgal biotechnology are turning their focus to high-value lipids for pharmaceutic, nutraceutic, and cosmetic products. Within microalgal lipid fraction, polyunsaturated fatty acids and carotenoids are broadly recognized for their vital functions in human organisms. Microalgal-derived phytosterols are still an underexploited lipid resource despite presenting promising biological activities, including neuroprotective, anti-inflammatory, anti-cancer, neuromodulatory, immunomodulatory, and apoptosis inductive effects. To modulate microalgal biochemical composition, according to the intended field of application, it is important to know the contribution of each cultivation factor, or their combined effects, for the wanted product accumulation. Microalgae have a vital role to play in future low-carbon economy. Since microalgal biodiesel is still costly, it is desirable to explore the potential of oleaginous species for its high-value lipids which present great global market prospects.

The Role of Photo-Cycles in the Modulation of Growth and Biochemical Profile of Microalgae: Part I—Food Interest Compounds

“…Varied abiotic effects have been reported to improve phytosterol production in some microalgae species. For example, sterol levels increased with a higher light period, mainly in eukaryotic microalgae [ 51 , 52 ]. In fact, eukaryotic microalgae, such as Scenedesmus obliquus , are reported in the literature as the most prominent strains for the production of sterols and are important to enable the cellular permeability of the membrane and maintain structural protection, highlighting in the environmental adaptation [ 21 , 53 ].…”

Cyanobacteria: A Natural Source for Controlling Agricultural Plant Diseases Caused by Fungi and Oomycetes and Improving Plant Growth

“…Cyanobacteria are often called "sustainable biofactories" for their sunlight-driven conversion of CO 2 into a renewable resource of high-value industrial products [37]. It is known that cyanobacteria synthesis pigments, lipids proteins, polysaccharides, and other compounds with proven bioactivity [38,39]. In addition to that, cyanobacteria have the ability to perform different ways of metabolism and the capacity to quickly switch from one to another as survival mechanisms of adaptation to extreme irradiation, temperature, pH, or salinity conditions generating a wide range of biologically active secondary metabolites [40][41][42][43][44].…”

Revisiting algal lipids and cellular stress-causing strategies for ameliorating the productivity of suitable lipids of microalgae for biofuel applications

“…2. 223,224 a photoinhibitory threshold. In some species, it promotes the lipid content, whereas in some, it has no effect or shows a regular decline in lipid concentration.…”

“…Fig.1Biosynthesis of fatty acids in microalgae. Showing the de novo biosynthesis of nutraceutically important omega-3 fatty acids, namely, EPA (eicosapantanoic acid), DHA (docosahexanoic acid), and DPA (docosapentanoic acid) found in the microalgae 223,224. …”