The Evolution and Versatility of Microalgal Biotechnology: A Review

Abstract

Microalgal biotechnology has emerged due to the health-promoting properties of microalgae related to their bioactive compounds and the great diversity of products that can be developed from algal biomass. Microalgal biomasses have been produced industrially for applications in different fields such as food, pharmaceutical, nutraceutical, cosmetic, and animal feed industries. They can be cultivated either in open systems or in closed systems (photobioreactors). Another important area is the use of microalgal biomass for energy production. It has become obvious that petroleum-derived fuels are unsustainable, due to depleting world reserves and greenhouse gas emissions. Microalgae can provide several different types of renewable biofuels. These include methane produced by anaerobic digestion of the algal biomass, biodiesel derived from trans-esterification of microalgal lipids, bioethanol produced from carbohydrate fermentations, and photobiologically produced biohydrogen. The idea of using microalgae as a source of fuel is not new. However, it is now being taken seriously because of increases in petroleum prices and, more significantly, the increasing concern about global warming as associated with burning fossil fuels. This review offers an update on information about microalgae, specifically emphasizing their biotechnological importance.

A review on microalgae cultivation and harvesting, and their biomass extraction processing using ionic liquids

“…Harvesting of microalgae from naturally occurring sources has been one of the oldest microalgae cultivation techniques known to man. The oldest record of microalgae harvesting was done by Aztec peoples where they harvest Spirulina from Lake Texcoco located at Mexico [13]. This cultivation method highly depends on naturally occurring water bodies to provide right condition and nutrients for the growth of microalgae.…”

Enigmatic Microalgae from Aeroterrestrial and Extreme Habitats in Cosmetics: The Potential of the Untapped Natural Sources

“…These polysaccharides with strong antioxidative properties belong to the active ingredients extracted from microalgae. Species rich in β-glucans were found in the aeroterrestrial red Porphyridium and in the cyanoprokaryote Nostoc flagelliforme [18,138], and it is possible to suppose that further studies will reveal more such algae.…”

“…These red unicellular algae are used to obtain the natural water-soluble pigments phycoerythrins and phycocyanins, which are considered alternatives to synthetic colorings due to their marginal toxicity [6,18,198]. These protein-containing pigments are also antioxidants and are used in lipsticks and eyeliners [18,138], while the phycocyanin extracted from Porphyridium purpureum has been applied in eyeshadows [18,152,199]. Its special use in decorative cosmetics is explainable by the fact that pigment does not change with pH (4 to 5) and the color remained constant under light [18,200].…”

The Potential Use of Marine Microalgae and Cyanobacteria in Cosmetics and Thalassotherapy

“…Furthermore, given that ß-1,3-glucan from plants and fungi appears to act as an anti-inflammatory [14], presumably this action would also be present in microalgal glucans, which would constitute an interesting field of research for the cosmetic sector targeting sensitive and reactive skin types. Species rich in ß-glucans are from the Chlorella genus and the Skeletonema diatom, as well as Porphyridium and Nostoc flegelliforme [23]. Skin is equipped with a very complex antioxidant system that protects it from oxidative damage due to intrinsic and extrinsic factors.…”

“…This mainly includes the photosynthetic pigments such as carotenoids, for example, the ß-carotenes from Dunaliella salina; astaxanthin from Haematococcus pluvialis (red color), has an antioxidant that is ten times more powerful than other carotenoids (such as ß-carotenes, zeaxanthin, etc. ), and 100 times stronger than alpha-tocopherol [23]; phycocyanobilins (blue pigment); and phycoerythrobilins from Spirulina and Porphyridium, which contain antioxidants and could be used in the decorative cosmetics industry (eye-liner and lipstick) [23]. Phycobiliproteins obtained from Porphyridium aerogineum are also used as colorants in food and cosmetics; this pigment does not change with pH (4 to 5) and the color remained constant under light [31].…”