NanoMicrobiol NanoBiotechnol, 2023 (2), 202324
Classification and application of algae in medical biotechnology and nanotechnology
Mahboobeh Bagheri 1*
1 Mehr Social Security Organization Hospital, Borazjan, Iran
* Correspondence: firstname.lastname@example.org
Algae is a wide group of organisms that have the power of photosynthesis. These creatures are one of the most adaptable organisms on the planet with a wide variety of species. These creatures can be found under salty waters to freshwater lakes and rivers. These organisms are natural inhabitants of moist soils, and can even be found in soils far from aquatic ecosystems. High adaptability, photosynthesis and no need for organic food and geographical population size make algae one of the main options in biotechnology. As far as a wide range of bioactive compounds used in pharmaceutical and medical sciences are obtained from these organisms. In recent years, the range of applications of algae has also entered the nanotechnology field and algae have been widely used in the biosynthesis of nanoparticles. Familiarity with algae physiology and classification of them can be useful in order to better understand these organisms and better use of these organisms. In this paper, we try to provide a proper classification of algae, the general characteristics of each category are also briefly described. Finally, we will look at the use of algae in biotechnology and pharmaceutical and medical nanotechnologies.
Keywords: Macroalgae; Microalgae; Medicine; Pharmaceuticals; Classification
Physiology or Philosophy is the science of the study of algae. Phycology is derived from the Greek word Phaecos, meaning sea moss. According to Frich’s 1935 definition, algae are all photosynthetic organisms that have not reached the distinct level of archaeondrial plants. These organisms lack barren envelope cells around their reproductive organs. In fact, reproductive structures are the main factors in distinguishing algae from plants and plant series. In algae, the reproductive structures are completely transformed into spores or gametes, and when spores or gametes are released, only the walls remain empty of reproductive organs, whereas in real plants reproductive structures are always complex and multicellular and only a few of the inner cells are involved in reproduction. Another difference between algae and excellent plants is that there is no texture differentiation in the form of roots, stems, leaves and vases. There are two main types of cells in algae, eukaryotic cells and prokaryotes. Prokaryotic algae, green-blue algae (cyanobacteria), lack membrane organelles. Because of their genetic and physiological similarities, this group is classified as a bacterium in new classifications. The rest of the algae are eukaryotes and have cellular organelles. Algae have four types of chlorophyll a, b, c and d. Secondary pigments include carotenoids and phycobili proteins. Breeding in algae is asexual and sexual (1).
2 Micro and macro algae
Microalgae is a group that is not visible to the naked eye. They are actually a diverse group of single-celled organisms, including eukaryotic and prokaryotic algae, which are visible to the naked eye when these single-cell algae bind together and come together. Today, some other microscopic algae such as diatoms and dinoflagells are considered as microalgae. Large-scale algae mainly include red and brown algae, which are called seaweeds (1).
3 Dispersion and spread of algae
Plants have a lot of dispersal in nature. Few organisms can grow in different environments like algae. These organisms can mainly be found in the aqueous environments and soil. Other algae live in air, hot springs, snow and ice, or coexist with plants and fungi.
4 Aquatic algae
Aquatic algae are divided into two groups of freshwater algae and saltwater algae. Fresh water refers to water with a salt concentration of less than 10 ppm, such as lake, river, pool and spring water. Salt water has salt content between 32 and 40 grams per liter. These environments include seas and oceans. In favorable conditions such as adequate food, light and suitable temperature, algae growth may be very rapid and their amount in water can increase greatly. Such a phenomenon is called bloom or algal bloom in the water. This occurs more often for blue-green algae than for other algae (2).
5 Soil algae
Algae are found in all kinds of soils. The number of algae in one gram of special soil may reach as much as one million. Algae are more abundant in wet soils and in mud. Despite the direct relationship between the percentage of moisture and the number of algae, these organisms are sometimes seen in dry soil, desert, and desert, and tolerate adverse environmental conditions for a long time. Soil algae live mostly on the surface due to the need for sunlight, but are sometimes found up to a depth of one meter of soil. In such conditions, algae live as saprophytes due to lack of sunlight and get their carbon from organic matter. Algae play an important role in soil biological processes, and the growth of algae in soils with organic matter helps other plants grow and increases soil fertility. The stabilization of air nitrogen by blue-green algae is one of the important phenomena that increases soil nitrogen. The presence of algae in the soil has other benefits, which can be briefly mentioned in raising and maintaining soil moisture, increasing soil organic matter, improving the texture and adhesion of soil particles (2).
6 Classification of algae
Historically, the study of algae was started by Linnaeus in 1735. He identified 14 genera of algae, only four of which were correctly identified. In 1836, Harvey identified four groups of blue, green, red and diatoms. This classification, based on the variety of colors found in algae, has been used for a long time. In 1932, Smith placed algae along with fungi in the talophytes and in the plant line. The first comprehensive classification was carried out by Fritzch in 1935. He divided algae into 12 families as following.
Consists of simple algae with prokaryotic cell structure, no nucleus and distinct chromatophore, and no mobile cells. Their pigments other than chlorophyll include phycocyanin and ficovarithrin. The product of their photosynthesis is sugar and glycogen and they do not have sexual reproduction.
Single-celled, mobile and green. It has a combination of plant and animal characteristics. Their reproduction is often in a binary dividing way.
Or green algae: they are very diverse. The nucleus and chloroplast are specific. The storage material of the cell is starch and has sexual reproduction.
Not much is known about this family.
They are yellowish green. The storage material of the cell is oil compounds. There are two numbers of flagellum with an unequal length.
Plants are primitive. Chloroplast is brown or orange due to phycochrysin pigmentation. Sometimes they lack cell walls. The storage materials are oil compounds. Moving cells often contain one, two, or three flagellae equal or unequal flagella. They often do not have sexual reproduction.
6.7 Bacillariophyceae or diatoms
The cell wall of algae in this category contains silica, chromatophore in yellow, brown, golden, bilateral, radial symmetry, and sexual reproduction.
Single cell and mobile. They have large brown or orange chloroplasts. Sometimes they lack cell walls. The storage material is fat cell. They have sexual reproduction.
Often single-celled and animated. Chromatophore is seen as a disc in yellow or brown color. Starch and oil make up the cell’s storage materials. Reproduction is often not sexual.
Most of these are seaweeds and brown is due to the presence of the pigment phocoxantine. Photosynthetic products are stored in the cells in the form of oil, alcohol, sugar and polysaccharides. They have sexual reproduction.
They often grow in the seas and oceans, and few are found in freshwaters. They are seen in green-blue and red. The product of photosynthesis is a type of starch called fluridine, and they have sexual reproduction.
Contains algae that have been found as fossils. In the new evolutionary classification of algae, it is considered that the cyanofeuceae, which has a prokaryotic structure, is considered the first and most primitive algae. However, the criteria for all classifications are characteristics such as the type of pigment and the structure of chloroplast or chromatophore, the storage materials of the cell and its structure, the type, number and location of flagella, the chemical composition of the cell wall and the characteristics of the nucleus.
7 Algae in biotechnology and nanotechnology
Microalgae produce many biologically active compounds, such as antibiotics, mosses, toxins, active pharmaceutical compounds and plant growth regulators. Most research has focused on toxins produced by cyanobacteria and dinoflagells. The production of secondary metabolites by microalgae changes with changing environmental conditions. When these processes are better understood, microalgae may become economically valuable sources for pharmaceuticals and other chemicals because production can be optimised in controlled cultures (3). Microalgae secrete vitamins, amino acids, fatty acids, siderophores, simple carbohydrates, and other substances that are essential or supportive for the growth of other microbes (3). Antibiotics are antimicrobial compounds produced naturally by an organism and are toxic to microalgae, bacteria, fungi, viruses, or protozoa differently (3). A mixture of fatty acids called chlorine (separated from chlorella chlorophyte) has antibacterial and utotoxic effects (3). Pesando showed that the photooxidation product of eicosapentaenoic acid from diatoma Asterionella saponica has potent antibiotic activity (3). A large number of fatty acid, carbohydrate and terpene compounds that have been isolated from microalgae have antibacterial and antifungal properties (3). Today, the importance of natural products is increasing due to nature’s high ability to synthesize special space compounds that have highly specific biological activity (3).
Recent studies have shown that the proportion of essential fatty acids in the human diet is associated with the spread of atherosclerosis and coronary artery disease. Seaweeds, which include microalgae, are at the end of the food chain and produce direct unsaturated fatty acids that are associated with a reduction in the incidence of heart disease. These algae mostly synthesize saturated and unsaturated fatty acids with the number of carbon atoms even. Many types of fatty acids are also synthesized with the number of individual carbon atoms, but their content is small. Microalgae synthesize saturated fatty acids similar to those commonly found in dry plants, but together with seaweeds, they make a greater variety of cisis unsaturated fatty acids that are nutritionally and therapeutically important (3).
Microalgae synthesize sterols and non-common and uncommon nanisoprenoids (3). L-asparaginase, isolated from Chlamydomonas sp. inhibits the growth of lymphosarcoma inoculated in CH3 mice (3). So far, various types of phycobiliproteins, anti-cancer and antibiotic agents, beta-carotene, xanthophyll, vitamin C and E, agricultural fertilizers, amino acids, single cell protein and oils have been isolated from microalgae (4). Most products from algae that are commercially registered in the industry are healthy food. Two major species cultured for this purpose are monocellular green algae Chlorella and more recently the stranded blue-green algae Spirulina. More than a dozen Spirulina and Chlorella plants have recently been set up in Japan and Taiwan, and Spirulina plants have also been set up in Mexico, Israel, Thailand and the United States. The overall production of healthy algal food is likely to be around 2,000 tons per year (based on dry weight). Algae are grown in ponds or fermenters and sprayed and then sold as tablets or powders. Some spirulina are used in Japan to extract phycocyanin, a blue pigment for edible use (4).
Algae as one of the organisms with the power of photosynthesis was introduced as adaptable and unexpected creature. Algae can be classified as Cyanophyceae, Oglenophyceae, Chlorophyceae, Chloromonadiaceae, Xantophyceae, Chrysophyceae, Bacillariophyceae, Cryptophyceae, Dinophyceae, Pheophyceae, Rhodophyceae, and Nematophyceae with divergent physiological and metabolic characteristics. So, these organisms are able to produce variety of bioactive compounds. Metal nanoparticles are one of the most recent materials which can be derived from algae.
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