What is the role of microbes in human welfare? What is the process behind the conversion of milk to curd? What is the role of microbes in sewage treatment? Read further to know more.
Microorganisms or microbes are microscopic living organisms that cannot be seen with the naked eye. Because these can only be viewed under a microscope, they have been given the name microorganisms. Some microorganisms are single-celled, such as bacteria, algae, and protozoa, whereas others, such as many algae and fungi, are multicellular.
Microbes may exist in a wide range of settings, from icy cold to scorching hot, and from deserts to marshy areas. Microorganisms can be both dangerous and beneficial.
Some microbes are helpful and contribute to human well-being. The role of microbes in human welfare is discussed below.
Microbes in human welfare
They aid in the production of bread and curd, the commercial production of alcohol and vinegar, the production of antibiotic medicines for disease treatment, improving soil fertility and cleaning up the environment by decomposing dead plants and animals, and the production of vaccines against a variety of diseases.
Vaccination and Antibiotics
When you become unwell, your doctor may prescribe antibiotic tablets, capsules, or injections, such as penicillin. Microorganisms are the source of these medicines.
These medications either destroy or inhibit the growth of disease-causing bacteria. These medications are known as Antibiotics.
A variety of antibiotics are now manufactured from bacteria and fungi. Streptomycin, tetracycline, and erythromycin are examples of well-known antibiotics derived from fungi and bacteria.
- Alexander Fleming was working on a culture of pathogenic bacteria [Staphylococci] in 1929. In one of his culture plates, he discovered the spores of a little green mould [Penicillium notatum]. He discovered that the presence of mould inhibited bacterial development.
- In fact, it also destroyed a large number of these germs. The mould penicillin was made from this.
- Antibiotics have substantially enhanced our ability to cure severe diseases like plague, whooping cough, diphtheria, and leprosy, which used to kill millions worldwide. We cannot envision a world without antibiotics now.
- Antibiotics used in excess may kill beneficial bacteria in the body.
- Antibiotics, on the other hand, are ineffective against colds and flu, which are caused by viruses.
- When disease-causing bacteria enter our bodies, the immune system generates antibodies to combat the intruder. The body also recalls how to combat the microorganism if it returns.
- When dead or weakened bacteria enter a healthy host, the body fights and kills them by creating appropriate antibodies. The antibodies remain in the body, protecting us from disease-causing microorganisms. This is how a vaccination function.
- Vaccination can prevent several diseases, including cholera, tuberculosis, smallpox, and hepatitis. In 1798, Edward Jenner discovered the smallpox vaccine.
Enzymes, chemicals, and other bioactive molecules
Microbes are also employed commercially and industrially to produce specific substances such as organic acids, alcohols, and enzymes. Acid manufacturers include:
- Citric acid fungus Aspergillus niger
- Acetobacter aceti (an acetic acid bacteria)
- Clostridium butylicum (a butyric acid-producing bacterium)
- Lactobacillus acidophilus (a bacterium).
- For the commercial manufacturing of ethanol, yeast (Saccharomyces cerevisiae) is utilised.
Lipases are enzymes that are used in detergent formulas to assist remove greasy stains from laundry. You’ve probably observed that bottled fruit juices from the store are clearer than those made at home. This is due to the employment of pectinases and proteases to clarify the bottled juices.
- Streptokinase, a clot buster produced by the bacterium Streptococcus and modified by genetic engineering, is used to remove clots from the blood arteries of patients who have had myocardial infarction leading to a heart attack.
- The fungus Trichoderma polysporum also produces cyclosporin A, which is utilised as an immunosuppressive medication in organ transplant patients.
- Statins, which are produced by the yeast Monascus purpureus, have been commercialised as cholesterol-lowering medications. It works by competitively blocking the enzyme responsible for cholesterol production.
Milk to Curd
- Lactobacillus and other microorganisms known as lactic acid bacteria (LAB) thrive in milk and convert it to curd.
- The LAB produces acids during growth that coagulate and partially break down the milk proteins.
- A tiny amount of curd added to fresh milk as an inoculum or starter contains millions of LAB that multiply at appropriate temperatures, converting milk to curd and improving its nutritional quality by boosting VITAMIN B12 [helps in the production of DNA and RBC] (red blood cells).
- Anaemia, severe neurological system damage, and other symptoms of vitamin B12 insufficiency].
- In our stomach, the LAB also plays an important function in preventing disease-causing microorganisms.
Yeast converts sugar into alcohol. Fermentation is the process of converting sugar into alcohol. In 1857, Louis Pasteur discovered fermentation.
- Bacteria ferment the dough, which is used to make dishes like dosa and idli. The puffed-up appearance of dough is caused by the emission of CO2 gas by the bacteria.
- Similarly, baker’s yeast is used to ferment the dough required to make bread (Saccharomyces cerevisiae).
- Fermentation by bacteria is also used to make a variety of traditional drinks and dishes. ‘Toddy,’ a popular drink from southern India, is prepared by fermenting palm sap.
- Microbes are also utilised to ferment foods such as fish, soya beans, and bamboo shoots.
- Cheese is one of the first foods to incorporate microorganisms. The big holes in ‘Swiss cheese’ are caused by a bacterium called Propionibacterium sharmanii producing a huge amount of CO2.
- Microbes, particularly yeasts, have been employed for centuries to produce beverages such as wine, beer, whisky, brandy, and rum.
- The same yeast Saccharomyces cerevisiae, often known as brewer’s yeast, is used for fermenting malted cereals and fruit juices to make ethanol for this purpose.
- Several varieties of alcoholic drinks are produced depending on the raw material used for fermentation and the style of processing (with or without distillation).
- Wine and beer are not distilled, but whisky, brandy, and rum are made by distilling the fermented broth.
Sewage treatment microbes
Sewage comprises a high concentration of organic materials and microorganisms. A large number of them are pathogenic.
- The primary sludge treats wastewater, and the supernatant is referred to as effluent. The primary settling tank effluent is collected for subsequent treatment.
- The principal effluent is routed into enormous aeration tanks, which are mechanically agitated and pumped with air. This enables the rapid development of beneficial aerobic microorganisms into flocs (masses of bacteria associated with fungal filaments to form mesh-like structures).
- These microorganisms devour the majority of the organic materials in the wastewater as they grow. This greatly reduces the effluent’s BOD (biochemical oxygen demand).
- The sewage water is treated till the BOD level is lower. The higher the BOD of wastewater, the more polluting it is.
- Once the BOD of sewage or wastewater has been sufficiently decreased, the effluent is fed into a settling tank to allow the bacterial ‘flocs’ to settle. This material is referred to as activated sludge.
- To serve as the inoculum or starter, a small portion of the activated sludge is fed back into the aeration tank.
- The residual sludge is poured into enormous tanks known as anaerobic sludge digesters. Other bacteria, which thrive anaerobically, consume the bacteria and fungi in the sludge here.
- Bacteria produce a combination of gases during digestion, including methane, hydrogen sulphide, and carbon dioxide. Because these gases are combustible, they combine to generate biogas, which can be used as a source of energy.
- The secondary treatment plant’s effluent is often discharged into natural water bodies such as rivers and streams.
Also Read : Bioremediation – ClearIAS
Microbes in biogas generation
Biogas is a gas combination (predominantly methane) created by microbial activity that can be used as fuel.
- Some bacteria that grow anaerobically on cellulosic material create a significant amount of methane [greenhouse gas] in addition to CO2 and H2.
- Methanogens are bacteria that produce methane. Methanobacterium is one such frequent bacterium. During sewage treatment, these bacteria are typically discovered in anaerobic sludge.
- These bacteria are also found in cattle rumen (a section of the stomach). A significant amount of cellulosic material found in cattle feed is also found in the rumen. These bacteria aid in the digestion of cellulose in the rumen and play a vital role in cattle nutrition.
- Therefore, cattle excreta (dung), often known as gobar, is high in these bacteria. Dung can be used to produce biogas, often known as gobar gas.
Biocontrol agents based on microbes
The employment of biological approaches to control plant diseases and pests is referred to as biocontrol. Biological agents are preferable to weedicides and insecticides. There is a method of pest management in agriculture that depends on natural predation rather than added insecticides.
- Bacillus thuringiensis is an example of a microbial biocontrol agent that can be introduced to control butterfly caterpillars (often written as Bt).
- The fungus Trichoderma is being developed as a biological control for the treatment of plant disease. Trichoderma fungi are free-living fungi that are abundant in root habitats. They are effective biocontrol agents against a variety of plant diseases.
- Pathogens called baculoviruses harm insects and other arthropods. It has been demonstrated that they don’t harm non-target insects, fish, birds, mammals, or even plants.
Microbes as biofertilisers
Biofertilizers are living things that improve the soil’s nutrient content. Biofertilizers are mostly derived from cyanobacteria, fungi, and bacteria.
You might be aware of the nodules that the symbiotic relationship between Rhizobium and leguminous plants causes to grow on their roots. These microorganisms convert atmospheric nitrogen into organic forms that the plant can utilise as nutrition.
- Azospirillum and Azotobacter are two examples of other bacteria that can improve the soil’s nitrogen content by fixing atmospheric nitrogen while growing freely in the soil.
- It is also known that fungi and plants can coexist in harmony (mycorrhiza). The genus Glomus has numerous mycorrhizal species. In these partnerships, the fungal symbiont takes up phosphorus from the soil and gives it to the plant.
- Further advantages include resistance to diseases carried by the roots, tolerance to salinity and drought, and an overall improvement in plant growth and development are all demonstrated by plants with these relationships.
- Many cyanobacteria, including Anabaena, Nostoc, Oscillatona, etc., are autotrophic microbes that can fix atmospheric nitrogen. They are found in both aquatic and terrestrial habitats.
- Cyanobacteria are a significant biofertilizer in paddy fields. Also increasing the organic content and fertility of the soil are blue-green algae.
The most frequent substances used to stop the growth of germs are salts and edible oils. They are therefore referred to as preservatives.
- To pickles, we add salt or acid preservatives to ward off microbial invasion.
- Common preservatives include sodium benzoate and sodium metabisulfite. They are also used to prevent spoiling in jams and squashes.
- For centuries, common salt has been used to preserve meat and fish. To prevent microbial growth, meat and fish are sprinkled with dry salt.
- Salting is also used to preserve amla, raw mangoes, tamarind, and other fruits and vegetables.
- Sugar is used to preserve jams, jellies, and squashes. Sugar lowers moisture content, preventing the formation of microorganisms that ruin food.
- Sugar lowers moisture content, preventing the formation of microorganisms that ruin food.
- Because bacteria cannot thrive in such an environment, the use of oil and vinegar avoids pickle deterioration. This method frequently preserves vegetables, fruits, seafood, and meat.
- Because pasteurised milk is free of hazardous germs, it can be drunk without boiling. The milk is heated to around 700 degrees Celsius for 15 to 30 seconds before being quickly chilled and stored.
- It suppresses microbial development in this way. Louis Pasteur discovered this method. It is known as pasteurisation.
Microbes are an essential part of life on Earth. Not all bacteria are harmful. Several bacteria are extremely beneficial to humans.
We virtually always use microorganisms and microbially generated goods.
From making curd and alcohol to cleaning up the environment, the role of microbes in human welfare is very important.
Microbes have been utilised for more than a century to treat sewage (wastewater) through the process of activated sludge formation, which aids in the recycling of water in nature.
Article Written By: Atheena Fathima Riyas
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