Many algae are used by human beings for food, manufacture iodine in some other purposes from ancient times. Many researches are being done in phycology (study of algae) and many workers are trying to find out the food value of algae, their importance in industries and importance in agriculture. The importance of role played by algae in the world is be coming more appreciated each day because of the increased utilization that many of them are valuable to man. Value is as under.
(1) Algae as food: Large numbers of Algae are used as source of food by human beings. They are rich in carbohydrates, inorganic substances and vitamins. Vitamins A C D and E are main constituents of these plants. Parphyratenesa is very popular and eaten throughout
. Kambu is another product of algae. Laminarta is used in Japan as standard food. Spirogyra is chief source of food ulva (sea lettuce) is also used be man as food. Recently green algae chlorena has drawn attention of psychologists. Percentage of Protein in this algae is too much than other vegetable or egg. It contains vitamins A to D. Algae is used to decorate pastries, sandwiches, rice, fish, cakes and jelly cakes in Japan . Agar Agar is also used in preparation of ice-cream and jellies. Geliduim, Gracillaria algae are chief source of agar agar. Another algae Rhodomenia palmata is chewed like tobacco in Japan . Hair vegetable is eaten in Scotland and algae Nostoc commune is one of its constituents. Minute algae chlorella has also been found as food source for human and animal. Many algae are used as food for animals like sheep, goat and cattle in China . New Zealand
(2) Algae in industry: Diatoms (an algae) prepare diatomaceous earth and is extensively used in sugar refineries and soap manufacture. It is also helpful in cement industry, in the manufacture of dynamite, rubber and blotting paper. It is also used in isolation of boilers, blast furnaces and at various other places where very high temperature (1000°C) is required.
Algin is extracted by boiling algae I washing soda solution and rollers of type writers are prepared from it. Japanese prepare artificial wool from sargassum. Agar-Agar obtained from algae like Geliduim is used I sizing of textiles. Algae chondrius and careragaenium which yields a mucilage is used in manufacture of left hats as stiffening agent. It has the properties of agar and therefore used as ingredient of cosmetics, shaving creams, shoe polishes and shampoos. Various red algae like lamineria yields Iodine. Several sea weeds also yield bromine, acetic acid, formic acid and acetone.
(3) Algae in Agriculture: Presence of mucilage in most of the members of Myxophyceae helps in development and better nourishment for nitrogen fixing bacteria. Some of them like Anebena, Nostoc etc are able to utilize and fix atmospheric nitrogen, thus increasing soil fertility. Some members of myxophyceae were able to fix 20 Lbs. of atmospheric nitrogen per acre in rice field.
(4) Medicinal Use of Algae: Green unicellular algae chlarella yield an antibiotic known as chlorellin. It is crystalline and stable at 120°C. With an average composition of carbon 77.3%, Hydrogen 16.6% and oxygen 10.99%. It has marked effect on gram positive and gram negative bacteria. Presence of chara and Nitella algae in a pond cause death of mosquito larvae thus helping in control of malaria to some extent.
(5) Algae in Biological research: Photosynthesis and metabolism are based on studies of unicellular algae such as chlorella. Certain algae like chlamydomonas are being used in genetical studies. Chlamydomonas was the first haploid organism on which successful hydridization was accomplished.
Certain algae like Aceta bularia, Valonia and Nitella show great success in studies on morphogenesis, nuclear function, nuclear cytoplasmic relationship and ionic exchange with the environment.
From above discussion it is clear that algae are great importance for human being.