Ecological and economic importance of algae

Ecological and economic importance of algae

1. ECOLOGICAL AND ECONOMIC IMPORTANCE OF ALGAE Submitted to, Ms.Merin Alice George Ass istant Professor Department of botany St Teresa's college Ernakulam Submitted by, Silpa Selvaraj I Msc Botany St Teresa's college Ernakulam

2. ALGAE AS FOOD More than 100 species, mostly of Phaeophyceae and Rhodophyceae , are used as food by man in different parts of the world.A few species of Chlorophyceae are also used as human food because of the presence of minerals, vitamins, carbohydrates and proteins, either in their cell wall or in their cytoplasm. Some of the important genera with their uses are mentioned below.

3. Among Phaeophyceae , some of the genera used as human food are Alaria, Laminaria, Sargassum, Durvillea, Undaria, Eisenia, Ecklonia and Pelvetia. In Japan, the food prepared from Laminaria i s called kombu , and the food from Alaria is called sarumen . In South America, Durvillea is collected, dried, salted and sold as Cachiyago . The contents of food value of brown algae include 6.l5% protein (with 17 amino acids), 1.56% fat and 57.04% carbohydrates. Many minerals along with carotene, thiamin and subflavine also found in brown algae. KOMBU Alaria Laminaria Eisenia Durvillea

4. Among Rhodophyceae , the important genera used as food are Porphyra, Palmaria, Chondrus,Gigartina, Gracilaria, Gelidium, Eucheuma and Rhodymenia . Porphyra is most important red alga used as human food. It is variously “called nori in Japan, laver in England and United States, sloke in Scotland, and luche in Southern Chile” Porphyra preparations are very rich in vitamins B and C. In Japan alone, 29.5 million kg of Porphyra per year is used as food. Palmaria is also eaten under different trade names in different countries, such as ‘ dulse ’ in Canada, ‘ sol ’ in Iceland and ‘ dillisk ’ in Ireland. Chondrus crispus is commonly called ‘ Irish moss ’ and used in ice-creams and various other foods. Gigartina stellata is used for the production of mucilage , which contains galactose sulphuric acid . Rhodymenia palmata is used as a common food ‘ dulse’ by fishermen. Glycerol, sorbitol and dulcitol are some of the carbohydrates found in red algae. Floridean starch , produced from Rhodophyceae, is a glucose. Nori Palmaria

5. Dulse Irish moss Gracilaria Gelidium Rhodymenia Porphyra

6. Among Chlorophyceae , the important algae used as food are Monostroma, Ulva, Codium, Chlorella, Caulerpa and Enteromorpha. Monostroma is used as a common food “ aonori ” in Japan. Ulva is dried, salted and sold as ‘ cachiyugo ’ similar to Durvillea. It is also used as salad. Codium is used as salad in Japan and many other countries. Chlorella is well-known for its high percentage of lipids and proteins. The Chlorella protein has all essential amino acids, and therefore it is used as a food in space-fl ights. Although Chlorella can be a good substitute for food in crisis, its culture is very expensive. According to Thacker and Babcock (1957), production of Chlorella is not economic. As it has an antibiotic, chlorellin , its use as a food is also discouraged. Aonori Ulva Chlorella Codium

7. Among the blue-green algae, Nostoc commune is used as a food called ‘ yuyucho ’ in China, Java, etc. Spirulina has a protein content in excess of 60% and is extensively cultivated (Shelef and Soeder, 1980). Diatoms are also used as food in some parts of the world. ■ Seaweeds are an excellent source of vitamins including vitamin C at levels equivalent to citrus fruits and vitamins A, D, B1, B12, riboflavin, niacin, pantothenic acid and folic acid. seaweeds also provide all the required trace elements for human nutrition Spirulina Diatom Nostoc

8. ALGAE AS FODDER Algae constitute a source of “permanent food” for many animals, including foxes, deer, rabbits and bears. These include mainly the members of Phaeophyceae, Rhodophyceae and some green algae. 1. Laminaria, Sargassurn, Fucus and Ascophyllum are used as fodder in many areas of the UK and Japan. 2 Macrocystis is used for cattle-feed because it is rich in vitamins A and E. 3.Hens, which feed on Ascophyllum-meal and Fucus meal, produce eggs with increased iodine content. 4. Seaweed-meals also increase the butter-fat content of the milk in feeding cattle. 5. A fish, named Tilapia, uses only the members of Cyanophyceae and Chlorophyceae as its food. Fucus Ascophyllum

9. 6. Many fishes depend for their food only on diatoms . 7. Stock-feed and commercial feed are regularly processed for many cattles, specially sheep and horses, from species of Laminaria, Ascophyllum and Fucus. 8.The major food of many fishes , protozoans, crustaceans and many other aquatic animals is provided by planktonic algae . 9. Rhodymenia is a common cattle-food in France. 9. In Japan, Pelvetia is used as a cow-feed. Pelvetia

10. ALGAE AS FERTILIZER Because of the presence of phosphorus, potassium and some trace elements, the seaweeds in many coastal regions of the world are used as fertilizer. They are either mixed with some other organic materials or are allowed to rot in the field as such. 1.Genera like Lithophyllum, Lithothamnion and Chara are used in the deficiency of calcium in the field. 2. Fucus is used as a common manure by Irish people. 3 Cyanobacteria has been used as a biofertilizer,as Symbiont inside Azolla into paddy fields since long time. Some of them are: Tolypothrix tenius, Aulosira fertilissima, Anabaena oryzae, Anabaenopsis arnoldii, Calothrix confervicola, Nostoc commune, and Cylindrospermum bengalense. 4. Several brands of liquid fertilizers prepared from seaweed are now available in the market. They are used in intensive gardening and greenhouse horticulture Chara Lithophyllum

11. ALGAE IN NITROGEN FIXATION Some Cyanobacteria have the capacity to fix atmospheric nitrogen. They include Nostoc, Anabaena,Aulosira,Calothrix,Nodularia,Scytonema,Oscillatoria, Cylindrospermum etc The nitrogen fixing capacity of heterocystous cyanobacteria is more in comparison to non heterocystous forms.

12. ALGAE IN MEDICINE 1.An antibiotic, chlorellin , is obtained from Chlorella . 2.Some antibacterial substances, effective against Gram-positive and Gram-negative bacteria, were also reported from Ascophyllum nodosum, Rhodomela larix, Laminaria digitata and some species of Pelvetia and Polysiphonia . 3.An antibiotic, effective against some bacteria, has been prepared from a diatom Nitzschia palea . It is specially effective against Escherichia coli. 4.People of maritime nations extensively use seaweeds as their traditional medicines as vermifuges, ointments and anaesthetics, as well as for the treatment of cough, gout, goitre, hypertension, veneral diseases and even for cancer 5.Iodine contents of Laminaria check goitre. 6. “ Tse-ko-Tsoi ”, an antihelmitic drug, is prepared from a red alga Digenia simplex in China Digenia simplex

13. 7. Fucoidin and sodium laminarin sulphate, obtained from some brown algae , are used as anticoagulant of blood. 8.Some algae are also used in the treatment of the diseases of kidney, urinary bladder and lungs. 9.Antiviral compounds, reported to be present in some red algae, are used in treating herpes viruses. 10. Extracts of Laminaria and Sargassum inhibit the growth of sarcoma and leukaemia cells in mice. 11.The saxitoxins produced by some dinoflagellates are used in some neurological disorders and neurobiological researches. 12. Scientists have recently succeded in isolating two important medicinal compounds from blue-green algae.One was the chemical cytonemin derived from Scytonema , and was found to be effective against skin cancer. The second was obtained from Tolypothrix , and is generally administered during heart attacks to improve blood circulation.

14. ALGAE IN INDUSTRIAL USES Petro l eum industry Algal biofuel, or algal oil is an alternative to liquid fossil fuels that uses algae as its source of energy-rich oils. Also, algae fuels are an alternative to commonly known biofuel sources, such as corn and sugarcane. When made from seaweed (macroalgae) it can be known as seaweed fuel or seaweed oil Eg: Chlorella, Scenedesmus, Chlamydomonas Scenedesmus

15. Kelp Industry : The kelp ash from these plants was widely bought by early industrialists for use in manufacture of soap, glass and alum. Many species of kelp are used as food for man, especially in the Orient. In Northern Europe they also serve as food for domestic animals, such as sheep and cattle. Fucus and Ascophyllum

16. Algin Industry : Algin occurs generally throughout the brown algae ( Laminaria, Macrocystis, Sargassum and Fucus ) as a cell wall constituent. It has remarkable water-absorbing qualities that make it useful in numerous industries in which a thickening, suspending, stabilizing, emulsifying, gel-forming, or film-form­ing colloid is required. algin provides ice cream with a smooth texture by pre­venting the formation of ice crystals. In automobile polishes it suspends the abrasive; in paints, the pigments; also in pharmaceuticals, the drugs and antibiotics. As a stabi­lizing agent it serves in the processing of rubber latex

17. Agar Industry : The outstanding use of the red algae, however, is in the production of agar. This is a dried and bleached gelatinous extract obtained from red algae— Gelidium nudifrons, G. pusillum, G. robustum, and Gracilaria verrucosa. Agar is used extensively in medicine, chiefly as laxative, since it is not digested and in­creases greatly in bulk with the absorption of water. Agar serves widely as a substitute for gelatin, as an anti-drying agent in breads and pastry, in improving the slicing quality of cheese, in the preparation of rapid-setting jellies and desserts, and in the manu­facture of frozen dairy products. More important than this medicinal utilization is its use as an essential ingredient in the preparation of medium for the growth of bacteria and fungi. As such it is indispensable in bacteriological laboratories, because no adequate substitute for agar is known.

18. Diatomaceous Earth Industry: Most species of Diatoms are marine, and when these minute plants die, they fall to the sea bottom Great deposits of this material, known as diatomaceous earth, are found in many parts of the world. Because diatomaceous earth is inert chemically and has unusual physical pro­perties, it has become an important and valuable material in industry. It makes an excellent filtering agent, which is widely used to remove colouring matters from pro­ducts as diverse as petrol and sugar. It is used in the manufacture of paints and varnishes, of phonograph records, and as a filler for battery boxes. Because of its hardness, it is used as an abrasive in scouring and polishing powders.

19. CARRAGEENINS Named after an Irish village Carrageenan, Carrageenin is primarily extracted from red alga Chondrus crispus and to a lesser extent from Gigartina spp. Two types kappa carrageenins & Lambda carrageenins. Used for making desserts,ice cream,milk shakes,condensed milk,shampoos, cosmetic creams,shoe polish etc Used in biotechnology as gels to immobilize cells and enzymes and in pharmaceuticals as an active excipient in pills and tablets.

20. FUNORI It is a sizing agent and glue for textile. Prepared from Gloepeltis furcata in Japan. It is a cell wall polysaccharide, structurally in between agar and carrageenin.

21. ALGAE IN BIOLOGICAL RESEARCH The cultures of Chlorella, Scenedesmus, Anacystis , etc. are widely used in many physiological researches, specially in the investigation of photosynthesis. Chlorella has been found very suitable for keeping the air in space vehicles pure on long interplanetary flights. The stale air in which the carbon dioxide has been concentrated is fed into a flood-lit con­tainer containing a mixture of water and nutrient chemicals and Chlorella.The alga restores oxygen into the space vehicle by its photosynthesis.

22. ALGAE IN SEWAGE DISPOSAL Sewage consists mainly of domestic and industrial wastes. The disposal of this sewage is mainly an aerobic process, and this oxygenation is facilitated mainly by some algae, e.g. Chlamydomonas, Chlorella, Euglena, Scenedesmus , etc. The aeration of sewage is essential, specially in smaller sewage bodies or ponds, to avoid unpleasant odour. ALGAE AS EXPERIMENTAL MATERIAL OR TOOL Acetabularia is used to study the material Inheritance of chloroplast genes. Chlorella is used to study the path of carbon in photosynthesis. Valvonia and Halicystis are used for experiments on the permeability of membranes. Chara and Nitella are well suited to experimental biosystematic investigations as they are easy to grow. Diatoms are used to test the resolution power of microscope lenses.

23. ALGAE AND LAND RECLAMATION Several Cyanobacteria like Anabaena, Nostoc and Scytonema have the capacity to reclaim usar soils. They grow on saline usar soils during rainy season and reduce the alkalinity of the soil ,thereby making it fit for paddy or other cultivation. ALGAE IN LENS PAPER Spirogyra is used in the manufacturing of lens paper for cleaning optical articles in Japan.

24. REFERENCES https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.slideshare.net/ssmvjunwani/economical-importance-of-algae . https://www.google.com/url?sa=t&source=web&rct=j&url=http://www.lscollege.ac.in/sites/default/files/e-content/Economic%2520imp. Sharma, O.P (1986) Series on Diversity of Microbes and Cryptogams: Algae (Tata McGraw Hill Education Private Limited) ●Ashok Kumar Awasthi (2015) Textbook of Algae (Vikas publishing house pvt ltd)