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Life hidden in the super-salty environment: Do you know how amazing "The Tenacious Dunaliella salina" is?
In extreme environments, the vitality of living things is almost astonishing. Today, we will explore an interesting microorganism called "Tough Dunaliella salina", which is a single-cell green algae that grows in hypersaline environments and is commonly found in salt lakes and salt evaporation ponds. Not only do these tiny organisms dominate primary production in extreme environments, they are also popular in nutraceuticals and cosmetics for their antioxidant properties.
History
Dunaliella salina was named by Emanoil C. Teodoresco of Romania and dates back to 1838, when Michel Felix Dunal of France first discovered this organism.
Initially, Dunal named it Haematococcus salinus and Protococcus, and later in 1905, Teodoresco and Clara Hamburger of Germany completely described and classified it as a completely new genus at the same time. Although both published research at the same time, Teodoresco is usually considered the founder of this classification because he published it earlier.
Habitat
The living environment of Duna cyanobacteria is extremely harsh, and the extremely high salt concentration makes it impossible for many organisms to survive. The secret of D. salina's survival lies in the high concentration of beta-carotene in its body to resist strong light, and glycerin to resist the effects of osmotic pressure. This makes them a superior choice for commercial production of beta-carotene.
The bright pink lake water has long been thought to be caused by this algae. However, a 2015 study of Lake Chulia in Australia found that the color of these lakes comes from the presence of several types of halophytic bacteria and archaea. .
Form and Characteristics
Species of the genus Dunaliella are morphologically similar to Chlamydomonas reinhardtii, the biggest difference being that they lack cell walls and contractile vacuoles. D. salina has two flagella of equal length and a cup-shaped chloroplast. The chloroplast often contains a central paste body that can store a large amount of β-carotene, making it orange-red.
The presence of beta-carotene not only provides D. salina with protection against long-term UV rays but also enables it to survive in environments with extremely high osmotic pressure.
The shape and symmetry of D. salina changes with environmental conditions. This species lacks a rigid cell wall and is therefore relatively susceptible to osmotic stress. In the saline environment in which it exists, glycerol is a key component in maintaining osmotic balance and enzyme activity.
Reproduction and Life Cycle
D. salina can reproduce asexually through motile vegetative cells or sexually through the fusion of two equal-length gametes to form a powerful zygote. According to research, sexual reproduction of D. salina decreases significantly when salt concentrations exceed 10%, but is induced at lower salt concentrations. Sexual reproduction begins when two flagella come into contact, and the zygote then germinates and releases up to 32 haploid daughter cells.
Commercial use
D. salina is the main driver behind primary production in hypersaline environments around the world, and its products are used in multiple industries.
β-carotene
Since the establishment of the first D. salina culture in the Soviet Union in 1966, which led to the production of β-carotene, the global commercial cultivation of this alga has become a halobiotechnology success story. Various technologies have emerged, ranging from low-tech mass cultivation to high-density fine cultivation.
Antioxidant and nutritional supplements
Due to its rich beta-carotene content, D. salina is a popular pro-vitamin A food supplement and cosmetic additive. More likely to be a source of vitamin B12.
Glycerin
There are also current attempts to develop high-concentration glycerol stored in D. salina for commercial production. However, the yield is technically feasible, but given the low economic efficiency, there are currently no biotechnological operations for glycerol production from algae.
Conclusion
The tenacious Dunaliella salina is undoubtedly a creature that thrives in extreme conditions, and its way of surviving and reproducing is full of life, making it a potential resource for commercial use. In such a challenging environment, D. salina has given us a lot of inspiration. Under these extreme conditions, is the continuous evolution of life not only a survival skill, but a profound understanding of the nature of life?
