Economic Importance of Algae
The economic importance of algae can be divided into two headings.
A. Beneficial roles of algae.
B. Harmful roles of algae.
A. Beneficial Roles of Algae
1.Primary Producers:
 Algae are the main Oxygen producers in aquatic areas. They are also useful in
decreasing water pollution by realizing Oxygen. 10% of photosynthesis is occurred by
the algae in total photosynthesis quantity.
2. Algae as Food
 Many freshwater and marine algae have been utilized as a direct source of food.
 Algae are rich in proteins, carbohydrates, oils, vitamins A,B,C and E and
minerals
Example
Cyanophyceae (or) Blue green algae – Nostoc & Spirullina
Brown Algae – Sargassum
Green Algae – Chlorella
3. Algae as fodder
 Many sea-weeds are directly used as feed for cattle, poultry and aquatic
organisms. Example: Laminaria and Fucus
 Sea-weed meal increases the egg-laying capacity of poultry.
4. Algae in Agriculture
a. Algae as Green Manure
 Sargassum, and Gracilaria are commonly used as green manures in agriculture.
 Sea weed manure increases the yield of barley, potato, coconut palms, citrus, etc.
b. Algae as Nitrogen Fixers (Biofertilizers)
 Many blue-green algae have the ability to fix the atmospheric nitrogen in the soil.
e.g.: Nostoc, Anabaena, Spirulina
c. Algae used for Reclamation of Soils
Saline and alkaline soils can be converted into productive soil by growing some blue-green
algae.
5. Algae in Industries
In industries, many algae have been used as sources for the extraction of commercial
products such as agar-agar, carrageenin, algin and diatomite.
a. Agar-agar
"
Agar agaf is a gelatinous, polysaccharide obtained from some red-algae such as Gelidium,
Gracilaria and Gigqrtina.
 Agar-agar is used for making artificial culture media for algae, fungi, bacteria and
plant tissues in biological laboratories.
 It is used as emulsifier in the preparation icecreams, fruit jellies and dairy products.
 It is used as sizing agent in leather and textile industries.
 It is used in paper making.
b. Algin
Alginic acid is extracted from Laminaria, Macrocystis andAscophyllum.
1. Alginic acid is used in making antibiotic capsules like aureomycin.
2. It is used as painting pastes in textile industry.
3. It is used as thickeners in cosmetics, pharmaceutical products, paints and polishes.
4.Alginates are used as emulsifiers in toothpaste^ice .creHfrjs etc.
5. They are also used in the production of plastics, rubber and artificial fibres.
c. Carrageenan
Carrageenan is a mucilaginous substance extracted from red alga Chondrus crispus and
Gigartina.
It is used in food industry, textiles, pharmaceutical industry and leather industry.
d. Diatomite
Diatomite is a rock like deposit formed by the deposition of siliceous cell walls of diatoms
over millions of years back.
Some of the uses of diatomaceous earth are1. Diatomite is used as filtering medium for oils and solvents.
2. It is used as cleaning agent for some solvents.
3. It catalyses dehydrogenation of vegetable oils.
4. It is used in the insulation of refrigerators, boilers, pipes, etc.
5. Algae in Sewage Disposal
 Some species like Chlamydomonas, Scenedesmus, Chlorella, Pondorhina, Euridina,
etc are living in sewage water.
 They are mainly useful to clean the water by realizing Oxygen.
 They also modified the carbonate material in the water into N, P, K fertilizers.
6.Algae and Research
 In biological research algae are useful because of their rapid growth, brief life span
and easy mode of cultivation.
 Chlorella, Scenedesmus and Anacystis are used in investigations in photosynthesis.
 Blue-green algae are used in studies on nitrogen fixation.
7.Algae Producing, Growth Hormones
Growth hormones like Indole acetic acid (IAA) is extracted from algae like Laminaria,
Fucus, etc.
8.Algae in Space:
Chlorella and Synechococcus are finding application in space ships and nuclear
submarines as oxygen regenerating and food and water recycling organisms.
Harmful aspects of Algae
 Some algae species like Microcystis, Lyngbya are develop water blooms in
water areas.
 They secrete toxic materials into water and polluted the water.
 Some algae species are caused for some skin diseases. Dianophlagellate is
caused for the death of fishes in water.