# Sustainable Microalgae and Cyanobacteria Biotechnology
## 2 Applications of Biotechnology on Microalgae and Cyanobacteria Utilization
### High Valuable Compounds from Microalgae
#### 2.1.1 Pigments
Apart from that, the sustainable and renewable properties of microalgaeulture, combined with a diverse pigment profile, have made microalgae a popular choice for the above-mentioned applications. All these pigments have been shown to be capable of being produced on a large scale from cyanobacterial and microalgal cultures grown under optimal conditions [12; 13]. Microalgae and cyanobacteria, as well as macroalgae, are a reliable source of natural bioactive compounds. Among pigments, carotenoids have shown significant commercial and industrial applications, with global demand increasing year after year. It was predicted that it would increase by 33 percent or reach 2.0 billion dollars in 2026 compared with 2019 [14]. This subsequently highlighted the promising market value with a variety of business opportunities. Along with these global market trends, green extraction technologies have emerged, which could provide new advantages in the sustainable production of these high-value products. Extraction technologies that have been widely reported in the extraction process for pigment carotenoids from algae samples include pressurized liquid extraction, supercritical fluid extraction, and subcritical fluid extraction [15]. Chlorophylls  
Chlorophylls (chl) are the primary light-harvesting toward energy-transforming pigments in photosynthetic organisms and are structurally arranged by non-covalentl bond to specific apoproteins [16]. Chlorophyll molecules, in general, have a tetrapyrrole ring with a central magnesium atom. Chlorophyll molecules are classified as chl a, b, c, and d, with structural differences in the side-group substituents on the tetrapyrrole ring. Apart from chl c, the chlorophylls a, b, and d are distinguished by the presence of long-chain terpenoid alcohol [17]. All chlorophylls have two major absorption bands, 450-475 nm for blue or blue-green and 615-675 nm for red, which results in the chlorophyll green color characteristic. Chl a is part of the core reaction center, a pigment-protein complex, located in the light-harvesting antennae component, accompanied by chl b or chl c. The accessory pigments, chl b, c, and d extend the broad range of light absorption. Thus, more energy can be captured from sunlight by the photosynthetic organism [18]. Chlorophyll derivatives (chl a, chl b, and chl c) in microalgae and cyanobacteria are promising for health-promoting activities such as anti-inflammatory properties, anti-colorectal cancer, human hygiene properties, anti-stomach disorder activities, and anti-bad breath protection [19]. A summary of previous research and development on the medical applications of chlorophyll and its derivatives has been published to provide a better understanding of science-based health claims [20]. Chlorophyll and its derivatives have structural functional properties and pharmaceutical properties. Photosynthesis is a process that converts solar energy into chemical energy by harvesting light energy along with water and carbon dioxide to produce oxygen and carbohydrates as byproducts. Based on the structural properties of chlorophyll, it contained a heme moiety part that was like the hemoglobin structure, which may serve to facilitate CO\({}_{2}\)/O\({}_{2}\) exchange by conferring the functionality to be used in the treatment of ulcers, stimulation of cell growth, acceleration of tissue formation, and increasing the rate of healing. Other chlorophyll derivatives have antioxidant and antimutagenic properties by trapping mutagens in the gastrointestinal tract [21]. Carotenoids  
Carotenoids are a large group of biological chromophores with an absorption range of 400 to 550 nm, at which wavelength the carotenoids have strong absorption, giving them their yellow-orange color [22].