Question

Give two uses of micro-organism?

Answer 1

Hint: Microbes are present everywhere in air, soil, water, inside our bodies and that of other animals and plants. They are present even at sites where no other life forms can exist, like deep inside the ocean, under the snow several meters thick and in highly acidic environments.

Complete answer:
They are used as biofertilizers. Inorganic farming these biofertilizers are used that provides optimum nutrients to crop plants. Biofertilizers are those organisms which help in enhancing nutrient quality in soil.

The main sources are bacteria, fungi and cyanobacteria. In bacteria rhizobium form symbiotic association with root nodules of leguminous plants.
• Bacteria: Azospirillum and Azotobacter are free living in the soil and fix atmospheric nitrogen, thus enriching the nitrogen content of soil.
• Fungi: Also form symbiotic associations with roots of higher plants known as mycorrhiza. Many members of the genus glomus from mycorrhiza. The fungal symbiont takes phosphorus from soil and passes it to plants. Plants that have such associations also show resistance for borne pathogens, tolerance to salinity and drought, and overall increase in plant growth and development. AS In return fungi get shelter and food from this association.

Second set of example:
• Curd: It is made up of those microorganism basically lactobacillus and others commonly called lactic acid bacteria (LAB) grow in milk and covert curd or in vinegar production with help of Acetobacter aceti, or in curd production which is done by lactobacillus.
• Bread: the dough is prepared to make bread which we usually eat . The dough is fermented using baker’s yeast (Saccharomyces cerevisiae). Puffed-up appearance of dough arises due to production of $CO_2$ gas during fermentation.

Note: Swelling of dough during bread making is known as leavening. It is caused by secretion of three enzymes by yeast-Amylase, maltase and zymase. In dosa-idli, the fermented preparation of rice and black gram, prepared by using bacteria.