[Biology Class Notes] on Useful Microorganisms Pdf for Exam

A microorganism, sometimes known as a microbe, is a microscopic organism that can exist as a single cell or as a colony of cells.

The possibility of unseen microbial life was suspected as early as the sixth century BC Jain scriptures in India. Anton van Leeuwenhoek observed microorganisms using a microscope in the 1670s. 

Louis Pasteur discovered in the 1850s that microorganisms spoiled food, disproving spontaneous generation. Robert Koch discovered microorganisms that caused tuberculosis, cholera, diphtheria, and anthrax in the 1880s.

Microorganisms exist in deserts, geysers, rocks, and deep oceans.

Evolution

About 3.5 billion years ago, single-celled microbes were the earliest forms of life to emerge on Earth. Further evolution was slow, and all species remained microbes for nearly 3 billion years throughout the Precambrian eon.

Microorganisms have a rather quick evolutionary rate. Most microorganisms can multiply quickly, and bacteria can readily exchange genes via conjugation, transformation, and transduction, even across species that are genetically very different.

Japanese scientists found a putative transitional microbe between prokaryotes and eukaryotes in 2012.

Microorganisms – “Uses”

Bacteria, fungi, viruses, and protozoa are all microorganisms. We almost always assume they’re bad. We know they harm plants and animals, including humans since we read about it. 

But microorganisms do serve us in numerous ways. Microorganisms aid in the manufacture of various foods, pharmaceuticals, environmental protection, manufacturing, and research. Hence, the uses are listed as below:

1. Dairy Products: The major participants are bacteria. Bacteria aid in fermentation, which aids in the production of curd, buttermilk, butter, and cheese. Streptococcus is the most commonly employed bacterial genus in commercial production.

2. Bread baking: To achieve the required fermentation, a species of Streptococcus is introduced to the dough before baking bread.

3. Alcoholic Drinks and Wines: Fermentation is used to create alcoholic beverages. Each drink starts with a different ingredient, such as potatoes or grapes. Then it’s fermented, distilled, and bottled. Yeast and other fungi are commonly used microorganisms.

4. Organic Acids: Fungi are used to make organic acids. Fungi like Acetobacter, Rhizopus, and Penicillium are used to ferment fruits and sugar-containing syrups.

5. Enzymes: Many microbes are utilized to make enzymes like lipase, lactase, protease, and peptidase.

6. Steroid: Some bacterial and fungal species are utilized to make steroids, which are then injected into the human body for various purposes.

7. Sewage Plant: Microorganisms are beneficial not just to our bodies, but also to the environment. They aid in sewage treatment’s secondary treatment stage.

8. Used as Insecticides: To keep some insects and pests away from crops, specific bacterial and fungal species are used.

9. Vitamin Production: Vitamin B12 is an essential vitamin that people require for efficient digestion. The production of B12 is carried out by fungi.

10. Biotech and research: Many labs use bacteria, fungus, and viruses to study diseases. Non-virulent versions of these microorganisms are injected into clinical trial patients. This aids in the future development of drugs, vaccines, and cures. And so do DNA and RNA research.

More about This Topic:

Microorganisms are a type of organism which is not visible to human eyes and hence called microscopic. There are various types of microorganisms, such as fungi, bacteria, protists, viruses, and archaea. Most of the microorganisms belong to the earliest life forms. Microbes can be parasitic or free-living. Many microorganisms are single-celled in other words, unicellular organisms. Microbes live everywhere on land, water, etc. Some of the microorganisms exist in the most extreme conditions and are called extremophiles. Microorganisms operate decomposition and hence are very vital in nutrient recycling. Even in the nitrogen cycle, microorganisms play a significant role. Not all microbes or microorganisms spread diseases. There are many which help in various natural processes and keep up the wellness of the ecosystem.

Free Living Microorganisms

The microbes that live free obtain energy in various ways. Some adapt to photosynthesis, just like plants — some help in breaking down natural chemicals and produce energy. Most of them feed on dead things due to which the decaying happens.

Parasitic Microorganisms

We call certain microbes as germs because they cause diseases. Such microbes are called parasites that survive by taking upon other living things. Parasites cause mumps, measles, and chickenpox. Such parasites are known as viruses. Storing and properly preparing food can avoid microorganisms from manifesting and spreading diseases.

Uses of Microorganisms

Microorganisms are omnipresent, and they are present in the food we eat, the air we breathe, the water we drink, the place we sit, stand, etc. They are cosmopolitan. They can even be present in the thermal geysers, vents, etc. (extremophiles).

Now, let us see various fields where microbes can help.

Microbes in Household Products:

• The conversion of milk into curd occurs due to the presence of lactobacillus bacteria.

• This lactic acid bacteria improves nutritional quality by enhancing vitamin B12.

• The dough we prepare for idli, dosa, is fermented using fungi and bacteria.

• Baker’s yeast (Saccharomyces cerevisiae) helps in the fermentation of bread.

• In many traditional drinks and foods, fermentation happens using bacteria. (Eg: Toddy).

• Microbes can help fish, soybean, and bamboo shoots in fermentation.

• Propionibacterium shermanii helps in the making of swiss cheese.

• Ripening of Roquefort cheese is done by growing fungi on them to produce distinct flavor.

Microbes in Industrial Products:

• Many antibodies and beverages can be manufactured using microorganisms.

• Yeast assists the fermentation process in the manufacturing of wine, Whisky, Rum.

• Saccharomyces cerevisiae or brewer’s yeast aids the fermentation of malted cereals, fruit juices to produce ethanol.

Microbes in Antibiotics:

• Penicillin, the first antibiotic discovered, is also developed using a microorganism known as Penicillium notatum.

• This penicillin helped in healing for wounded soldiers during world war II.

• Some other fatal diseases like Plague, whooping cough, Diphtheria, and leprosy can be treated using these antibiotics produced from microorganisms.

Microbes in Sewage Treatment:

Bacteria help to treat sewage water from municipal waste. It uses anaerobic respiration, BOD, etc. to tre

Microbes in Production of Biogas:

Methanogen bacteria help in the production of biogas.

Microbes in chemicals, enzymes, and other bioactive molecules:

• Aspergillus niger is present in citric acid. It is a fungus.

• Acetobacter acetic is available in acetic acid.

• Clostridium butylicum bacteria in butyric acid.

• Lactobacillus is present in lactic acid.

• Lipases are an essential part of detergents.

• Pectinases help in storing the bottled juices.

• Streptokinase enzyme used to remove blood clots from the blood vessels of myocardial infarction patients.

• Cyclosporin A acts as an immunosuppressive agent, and  Cyclosporin A enzyme is produced by the eubacterium Trichoderma polysporum.

• Monascus purpureus yeast produces statins which are used as blood cholesterol-lowering agents.

Microbes are used in various parts of our day to day life, including some industries, and they are equally useful for nature.

• Some fungi and bacteria species help in the creation of steroids, which are used to inject humans for various purposes.

• Specific bacteria and fungi are also used to create protection from some insects and pests in agriculture.

• Microbes play a vital role in keeping up the soil fertility. They do the process of composting and help in the formation of manure. This manure improves the fertility of the soil by enhancing nutrients such as nitrates.

• Microbes are vastly used in the research field. The creation of various vaccines is also aided by microbes and research using them.

• Microbes assist in the analysis and research done on DNA and RNA.

• Microbes can take or consume nitrate from the air, and hence they are essential in the nitrogen cycle.

Conclusion

Microorganisms or microbes have existed in nature for a very long time. Microbes have evolved quickly and have become useful for the environment as well as for living beings.The existence of both harmful and good bacteria provides a proper balance in the ecosystem. Microbes come under the bad category if they aid in spreading diseases and harming other living beings. Microbes come under a good category if they help in various productions such as yeast, curd, steroids and so on. A lot of research work is done on the microbes, and various vaccines use microbes. There are innumerable uses of bacteria in the ecosystem, some of which may have not been found yet. Microbes are the backbone for production industries, especially food-related. Without microbes, the production of curd will cease to exist, and also bread will no longer be part of the food for living beings like humans. Hence bacteria have a bad side and a good side as well. The bad side has to stay under control, and the good side must not get exploited, which will keep a balance in the ecosystem.