Cyanobacteria : General Characters & Economic Importance

In this article we will discuss about:- 1. General Characters of Cyanobacteria 2. Importance of Cyanobacteria

1. General Characters of Cyanobacteria

• Mostly cyaobacteria are aquatic and some are terrestrial.
• The organisms are prokaryotic. They may be unicellular, colonial.
• Cell wall is composed of cellulose.
• Flagella are absent. Mesosomes are absent like bacteria.
• They contain photosynthetic pigments, so they are autotrophs.
• No sex organs are produced and sexual reproduction is absent.
• They reproduce asexually.
• One of the important members of cyanobacteria is Nostoc

2. Importance of Cyanobacteria

1. They are one of the early colonizers of bare and barren areas. They provide suitable conditions for the growth of other organisms even in the most hostile environment.

2. Blue green algae function as food to several aquatic animals. Spirulina is regularly collected for human consumption in parts of Africa. Nostoc is similarly used in China. In Rajasthan Anabaena and Spirulina are collected from Sambar Lake and used as fodder and manure. Spirulina is very easily cultivated in tanks and can be used as a palatable protein rich food supplement for humans and animals.

3. Several cyanobacteria have the ability of nitrogen fixation. The filamentous forms possess special large pale cells or heterocyst’s for this. Some of the fixed nitrogen comes out as excretion. After death of cyanobacteria the substratum becomes rich in nitro­gen. Such nitrogen fixing cyanobacteria are now regularly inoculated in the rice fields. This saves consumption of nitrogen fertilizers.

4. Nitrogen fixing cyanobacteria are often used for reclaiming usar soils, e.g., Nostoc, Anabaena. These cyanobacteria produce acidic chemicals for counteracting alkalinity of the soil and nitrogenous compounds which are generally deficient in these soils.

5. Antibiotic can be manufactured from extract of Lyngbia.

6. Species of Anabaena and Aulosira do not allow mosquito larvae to grow nearby. Such cyanobacteria can be inoculated in village ponds and rice fields to prevent the growth of mosquitoes.

7. Cyanobacteria can grow on the walls and roofs of buildings during the rainy seasons causing discolouration, corrosion and leakage.

8. They produce water blooms, imparting bad odour and colour to water bodies.

9. Some cyanobacteria produce toxins harmful to most aquatic animals. They may prove equally toxic to human beings drinking or bathing in such water. The important toxins producing cyanobacteria are Microcytic aeruginosa (= Anacystis cyanea), Anabaena flosaquae, Aphanizomenon flos-aquae.