Worldwide, research has been conducted on the development of anti-oxidant, health-protecting and enhancing products derived from microalgae. The combination of microalgae is also a trend to create products that fully supplement the ingredients that work together to fight oxidation and enhance the body’s immune function. In Europe, the US, Japan and some developed countries, nutritional supplements and functional foods derived from microalgae are used to increase anti-oxidant capacity, enhance immunity, prevent and support cancer treatment.

Among the potential microalgae species, Spirulina (Arthrospira platensis), Chlorella vulgaris and Dunaliella salina are three species of algae that are of particular interest in the world. The reason is that Arthrospira platensis is widely cultivated in the world, but in Vietnam it is still limited, the current output does not meet the domestic demand for functional foods, feed for aquaculture and the price is still quite high compared to the world, especially China. In addition, Spirulina is rich in phycocyanin, an important target compound that plays an antioxidant role, preventing and supporting cancer treatment. For Chlorella vulgaris, this is an algae species with a high content of chlorophyll a/b, a growth stimulant and rich in unsaturated fatty acids and vitamins, so this algae species is exploited for biomass in Japan and Germany to make superfoods for humans. The Dunaliella salina algae species is particularly rich in carotenoid compounds that have antioxidant properties, prevent free radicals, and enhance immune response.

In Vietnam, health protection products derived from microalgae are still limited. Up to now, only Spirulina algae products are known and used by a segment of consumers. Meanwhile, green algae Chlorella vulgaris and Dunaliella salina have not received much attention in Vietnam as food supplements for humans and algae. Therefore, research on cultivating these algae species is necessary to collect biomass and develop products.

Based on the above reality, Project Manager  Nguyen Duc Bach  and the research team at the Vietnam Academy of Agriculture carried out the project  “Research on technology for producing products rich in antioxidants from 3 species of microalgae Chlorella vulgaris, Arthrospira platensis and Dunaliella salina”  with the following objectives: The research is to study the process of cultivating, harvesting biomass, and extracting bioactive compounds from 3 species of microalgae Spirulina (Arthropira) platensis, Chlorella vulgaris and Dunalliellasalina; Extracting active ingredients, mainly the pigments Chlorophyll, Carotenoid and Phycocyanin from the 3 species of microalgae above and determining the antioxidant activity in vitro, in vivo as a scientific basis for product development; Developing supplementary products derived from 3 species of microalgae with the ability to fight oxidation, prevent free radicals and prevent and support cancer treatment will bring benefits to protect and improve public health.

After a period of research, the topic has obtained the following results:

Factors affecting the growth of three microalgae species A. platensis, C. vulgaris, and D. salina were determined, including temperature conditions, nutrient medium, and monochromatic LED lighting conditions. For D. salina, the influence of osmotic pressure using 4M NaCl and 20 klux lighting intensity was investigated. Conditions for cultivating three microalgae species A. platensis, C. vulgaris, and D. salina in raceways and photobioreactors were determined, of which A. platensis and C. vulgaris can be cultivated in photobioreactors due to their ability to withstand pipeline pressure. D. salina is suitable for cultivation in raceways. Of which, for Dunaliella salina, the most suitable cultivation temperature is 20-25oC, using fluorescent light. (2500- 3000 Lux), pH 7.5, NaCl concentration 3.5-4% suitable for algae growth. D. salina cell density is controlled by measuring optical density at 725 nm wavelength.

Maximum stocking density reaches 3,106 cells/ml. For the widely adaptable green algae Chlorella vulgaris, in which BBM medium is suitable for the strain. Suitable stocking temperature is from 20-25oC, fluorescent light 2500 Lux, environmental pH: 7.5, lighting 16:8 (light/dark). Aeration with compressed air (through filter), continuous aeration at a rate of 5 liters/minute in a 2 liter stocking tank (stocking volume 1.5 liters). Stocking density: C. vulgaris and D. salina are stocked at a density of 5,104 cells/ml. Stocking density of A. platensis measured at OD750 after adding stock reaching OD750 of about 0.125 is suitable. Increasing the density helps shorten the stocking process.

The main active groups in three species of microalgae were extracted and the antioxidant and cytotoxic properties of semi-finished and finished products were evaluated.

The standardized dry powder enriched with chlorophyll, phycocyanin and carotenoids of three microalgae species was prepared.

Antioxidant hard capsules have been prepared from 3 species of microalgae. The process and pharmaceutical ingredients for the hard capsules have been established. From the survey of excipients, the formula and process for preparing antioxidant hard capsules have been established; The product’s TCCS has been developed and evaluated and tested at the National Institute of Food Safety and Hygiene and issued a certificate of publication.

                                                                    Sourse: The full text of the research report (code 20319/2021) can be found at the National Center for Science and Technology Information.