Клорелла – жасыл балдырлар туысы

Genus of green algae
the genus of algae

Chlorella is a genus of about thirteen species of single celled green algae of the division Chlorophyta. The cells are spherical in shape, about 2 to 10 μm in diameter, and are without flagella. Their chloroplasts contain the green photosynthetic pigments chlorophyll a and b. In ideal conditions cells of Chlorella multiply rapidly, requiring only carbon dioxide, water, sunlight, and a small amount of minerals to reproduce. The name Chlorella is taken from the Greek χλώρος, chlōros/ khlōros, meaning green, and the Latin diminutive suffix ella, meaning small. German biochemist and cell physiologist Otto Heinrich Warburg, awarded with the Nobel Prize in Physiology or Medicine in 1931 for his research on cell respiration, also studied photosynthesis in Chlorella. In 1961, Melvin Calvin of the University of California received the Nobel Prize in Chemistry for his research on the pathways of carbon dioxide assimilation in plants using Chlorella. Chlorella has been considered as a source of food and energy because its photosynthetic efficiency can reach 8%, which exceeds that of other highly efficient crops such as sugar cane.

Chlorella was first described by Martinus Beijerinck in 1890. Since then, over a hundred taxa have been described within the genus. However, biochemical and genomic data has revealed that many of these species were not closely related to each other, even being placed in a separate class Chlorophyceae. In other words, the "green ball" form of Chlorella appears to be a product of convergent evolution and not a natural taxon. Identifying Chlorella like algae based on morphological features alone is generally not possible. Some strains of "Chlorella" used for food are incorrectly identified, or correspond to genera that were classified out of true Chlorella. For example, Heterochlorella luteoviridis is typically known as Chlorella luteoviridis which is no longer considered a valid name.

When first harvested, Chlorella was suggested as an inexpensive protein supplement to the human diet. According to the American Cancer Society, "available scientific studies do not support its effectiveness for preventing or treating cancer or any other disease in humans". Under certain growing conditions, Chlorella yields oils that are high in polyunsaturated fats—Chlorella minutissima has yielded eicosapentaenoic acid at 39.9% of total lipids.

Following global fears of an uncontrollable human population boom during the late 1940s and the early 1950s, Chlorella was seen as a new and promising primary food source and as a possible solution to the then current world hunger crisis. Many people during this time thought hunger would be an overwhelming problem and saw Chlorella as a way to end this crisis by providing large amounts of high quality food for a relatively low cost. Many institutions began to research the algae, including the Carnegie Institution, the Rockefeller Foundation, the NIH, UC Berkeley, the Atomic Energy Commission, and Stanford University. Following World War II, many Europeans were starving, and many Malthusians attributed this not only to the war, but also to the inability of the world to produce enough food to support the increasing population. According to a 1946 FAO report, the world would need to produce 25 to 35% more food in 1960 than in 1939 to keep up with the increasing population, while health improvements would require a 90 to 100% increase. which Science News Letter turned into "future populations of the world will be kept from starving by the production of improved or educated algae related to the green scum on ponds." The cover of the magazine also featured Arthur D. Little's Cambridge laboratory, which was a supposed future food factory. A few years later, the magazine published an article entitled "Tomorrow's Dinner", which stated, "There is no doubt in the mind of scientists that the farms of the future will actually be factories." Science Digest also reported, "common pond scum would soon become the world's most important agricultural crop." However, in the decades since those claims were made, algae have not been cultivated on that large of a scale.

Since the growing world food problem of the 1940s was solved by better crop efficiency and other advances in traditional agriculture, Chlorella has not seen the kind of public and scientific interest that it had in the 1940s. Chlorella has only a niche market for companies promoting it as a dietary supplement. After a decade of experimentation, studies showed that following exposure to sunlight, Chlorella captured just 2.5% of the solar energy, not much better than conventional crops.

Chlorella is consumed as a dietary supplement. Manufacturers of Chlorella products falsely assert that it has purported health effects, including an ability to treat cancer, The United States Food and Drug Administration has issued warning letters to supplement companies for falsely advertising health benefits of consuming chlorella products, such as one company in October 2020. There is some support from animal studies of chlorella's ability to detoxify insecticides. Cholerella protothecoides accelerated the detoxification of rats poisoned with chlordecone, a persistent insecticide, decreasing the half life of the toxin from 40 to 19 days. The ingested algae passed through the gastrointestinal tract unharmed, interrupted the enteric recirculation of the persistent insecticide, and subsequently eliminated the bound chlordecone with the feces.

A 2002 study showed that Chlorella cell walls contain lipopolysaccharides, endotoxins found in Gram negative bacteria that affect the immune system and may cause inflammation. However, more recent studies have found that the lipopolysaccharides in organisms other than Gram negative bacteria, for example in cyanobacteria, are considerably different from the lipopolysaccharides in Gram negative bacteria.