Nitrogen Fixation
* Some micro organisms reside in the root nodules of leguminous plants. They can fix nitrogen from the air into the soil, and increase soil fertility.
* Some bacteria and blue green algae present in the soil fix nitrogen from the atmosphere and convert it into nitrogenous compounds.
* Some micro organisms decompose organic waste, including dead plants and animals, into simple substances and clean up the environment.
* Certain bacteria covert the compounds of nitrogen present in the soil into nitrogen gas, which is released into the atmosphere.
Useful Role of Bacteria
* Bacteria play a useful role n medical, agriculture and industrial fields.
* Some uses of bacteria in the medical field are in the production of antibiotics, serum, vaccines and toxoids.
* Nitrogen – fixing, ammonifying, nitrifying and denitrifying bacteria play a useful role in agriculture and in the nitrogen cycle.
* Some industrial uses of bacteria are in tea curing, tanning and retting.
* Bacteria play an important role in decay and putrefaction, and in the synthesis of vitamins and minerals.
* Bacteria are used in sewage treatment plants and biogas plants.
Microbes in Industrial Products
* Saccharomyces cerevisiae, also known as brewer’s yeast, ferments different malted cereals and fruit juices to produce ethanol.
* Other than alcoholic beverages microbes help in the industrial production of antibiotics, chemicals, enzymes and other such bioactive molecules.
* Microbes also produce chemicals such as organic acids and enzymes.
* Bacteria and fungi are also used in microbiological cultures, where they are grown on nutritive solutions and allowed to colonise so that they can be studied.