Question

Find out the role of microbes in the following and discuss it with your teacher.

(a) Single cell protein(SCP)
(b) Soil

Answer 1

(a) Single cell protein(SCP)
A single cell protein is a protein obtained from certain microbes which forms an alternate source of proteins in animal feeds. The microbes involved in the preperation of single cell proteins are algae yeast or bacteria. These microbes are grown on an industrial scale to obtain the desired protein. For example Spirulina can be grown on waste materials obtained from molasses sewage and animal manures. It serves as a rich supplement of dietry nutrients such as proteins carbohydrate fats minerals and vitamins. Similarly micro-organisms such as Methylophilus and methylotrophus have a large rate of biomass production. Their growth can produce a large amount of proteins. 
(b) Soil
Microbes play an important role in maintaining soil fertility. They help in the formation of nutrient-rich humus by the process of decomposition. Many species of bacteria and cyanobacteria have the ability to fix atmospheric nitrogen into unusable form. Rhizobium is a symbiotic bacteria found in the root nodules of leguminous plants. Azospirillium and Azotobocter are free living nitrogen-fixing bacteria whereas Anabena Nostoc and Oscillitoria are examples of nitrogen-fixing cyanobacteria.