5. Classification and economic importance of algae

Some of them, such as blue-green algae, are organisms that fix the atmospheric nitrogen into the soil. This fixation of atmospheric nitrogen increases the fertility of the soil.

  

Red algae such as Gelidiumand Gracillariaare used to extract Agar-Agar which is further used to prepare growth medium in laboratories and make ice creams and jellies in food industries.

  

It is obtained from brown algae like Laminaria.

  

Chlorella pyrenoidosa is used in space travel to get rid of the carbon dioxide and decompose the human waste.

  

Single-cell algae such as blue-green algae are used in the production of protein.