Microbes in Human Welfare: Explanation and Importance

Microbes in human welfare play essential role in many aspects of our lives, from health maintenance to agricultural and environmental sustainability. They are present almost everywhere such as in soil, water, humans, animals, plants, air, etc. Viruses, bacteria, fungi, algae, and protozoa are some examples of microbes. They are also responsible for causing disease in human and such microbes are called pathogens.

• They are microscopic unicellular organisms that can only be visible through a microscope.
• Microbes have various applications in the manufacturing of food, household products, sewage treatment, biocontrol agents, etc.
• Among the diverse populations of microorganisms, some microbes also play an important role in human welfare.   ^t

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What are Microbes?

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Microbes or microorganisms are small microscopic organisms that cannot be seen with the human eyes. Examples of microbes in human welfare include bacteria, fungi, protozoa, archaea, protists, and viruses. Some microbes are also beneficial such as lactobacillus bacteria, used in formation of curd from milk. A few microorganisms are also harmful and can cause diseases like malaria, dengue, toxoplasmosis, etc.

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Microbes in Human Welfare

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Microbes in human welfare account for 60% of living matter on the earth and thus become an important component of the ecosystem. Despite the harmful effects of some microbes, it is important to highlight the importance of microbes in human welfare. Microorganisms help in digestion, agriculture farming, cleaning the environment, and nitrogen fixation of the soil.

These microbes are important in various areas, including:

• Household products
• Industrial products
• Sewage treatment
• Production of biogas
• Microbes as biocontrol agents
• Microbes as biofertilizers

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Microbes in Household Products

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You might have seen your mother adding a small amount of curd (inoculum) to fresh milk which then turns into curd! The reason behind this is the presence of germs. Here are some more benefits of microbes in human welfare used as household products. Microbes such as Lactobacillus, commonly known as lactic acid bacteria [LAB], convert milk into curd.

• This organism coagulates the milk and digests milk proteins which also increases B₁₂ content.
• Dough used to make bread, dosa and even idli use Saccharomyces cerevisiae which ferments the dough, giving it a puffed-up appearance.
• Toddy, a traditional drink in the southern part of India, is made from fermented plant sap.
• There are a variety of cheeses and each type has a different microbe involved. 
• Swiss cheese is produced by a bacterium named Propionibacterium shermanii, which produces a large amount of CO₂ creating holes.
• The roquefort cheese has a specific flavour due to presence of fungus.

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Microbes in Industrial Products

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Even in industry, microbes are utilized to synthesize a variety of human-valued products such as beverages and antibiotics. On an industrial scale, microbes are grown in very huge vessels known as fermentors.

Microbes in Beverage Production

Microbes in human welfare, particularly yeasts, are used to produce drinks such as wine, beer, whiskey, brandy, and rum.

• Saccharomyces cerevisiae, often known as brewer's yeast, is used for fermenting malted cereals and fruit juices to make ethanol for this purpose.
• Different varieties of alcoholic drinks are produced depending on the raw material used for fermentation and the method of processing (with or without distillation).
• Wine and beer are made without distillation, but whiskey, brandy, and rum are made by distilling fermented broth.

Microbes in Antibiotics Production

Microbes in human welfare are used to make antibiotics, such as the first antibiotic penicillin, which was developed by Alexander Fleming using the mould Penicillium notatum. Antibiotics are chemical substances produced by certain microbes that can kill or inhibit the growth of other (harmful) microbes.

• Antibiotics are one of the most significant discoveries of the 20th century, revolutionizing healthcare and saving countless lives.
• The antibiotic was widely used for the treatment of wounded soldiers during the war.
• Various antibiotics have been produced by microbes allowing is to deal with deadly diseases.
• Diseases such as whooping cough, plague, diphtheria are treatable now.

Chemicals, Enzymes, and other Bioactive molecules

Microbes are also used commercially and industrially to produce certain chemicals such as organic acids, alcohols, and enzymes. The examples of microbes in human welfare includes: 

• Aspergillus niger (a fungus) produces citric acid.
• Acetobacter aceti (a bacterium) produces acetic acid.
• Clostridium butylicum (a bacterium) produces butyric acid.
• Lactobacillus (a bacterium) produces lactic acid.

Microbes are used to make enzymes, which are like tiny tools that help with different chemical reactions.

• Lipases are enzymes that break down fats.
• They are used in laundry detergents to remove oily stains.
• Pectinases and proteases are enzymes that help clear up cloudy liquids.
• They are used to make bottled fruit juices look clearer.
• Streptokinase is an enzyme that helps break down blood clots. It is used to treat heart attacks.

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Microbes in Sewage Treatment

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A large amount of wastewater is produced every day by cities and towns. Wastewater is known as sewage, and its major component is human excreta. Sewage is rich in organic matter and microbes and sewage water is treated in sewage treatment plants before disposal into water bodies. There are two main steps in sewage water treatment: Primary Treatment & Secondary Treatment.

Primary Treatment

In the first step, the physical particles such as debris and grit are removed. Residues are removed through sequential filtration and the remaining particles are eliminated through the process of sedimentation. The sediments form the primary sludge, and the supernatant creates the effluent used for the secondary treatment.

Secondary Treatment

This treatment is also known as the biological treatment. The effluent from primary treatment is sent into large aeration tanks, and the air is pumped into it followed by mechanical agitation. The aeration causes flocs to develop (masses of bacteria associated with filamentous fungus), creating a mesh-like structure. This reduces the biochemical oxygen demand (BOD) as the organic matter in the water is consumed. The Ministry of Forest and Environment has initiated the Ganga Action Plan and Yamuna Action Plan to prevent river water pollution.

• BOD refers to the amount of oxygen that would be consumed if all the organic matter in one litre of water is consumed.
• The higher the BOD more polluted the water. Once the BOD is reduced, the water is passed to settling tanks.
• The flocs settle down to form the activated sludge, some of which serve as the inoculum for the aeration tank.
• The rest of the sludge is sent to the anaerobic sludge digesters, where bacteria grow anaerobically and digest other bacteria and fungi.
• During anaerobic digestion, various other gases such as methane, hydrogen sulphide and carbon dioxide are also formed.
• This mixture of gases is known as biogas and is used as a fuel.
• The effluent from secondary treatment is released into the water bodies. 
• Many rivers today have been polluted due to sewage directly being thrown into water bodies.

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Microbes in the Biogas Production

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Biogas is a mixture of gases that consist of methane, carbon dioxide and hydrogen. A group of bacteria known as methanogens, specifically Methanobacterium, grows anaerobically on cellulosic material. Excreta of cattle, commonly known as gobar, is rich in this material and is used in biogas plants. This is also a classical example of microbes in human welfare. The technology of biogas plants in India was developed by the Indian Agricultural Research Institute (IARI) and Khadi and Village Industries Commission (KVIC).

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Microbes as Biocontrol Agents

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Biocontrol refers to the use of biological and natural methods in controlling pests and plant diseases. Increased use of chemicals is extremely harmful to humans, and thus the use of natural processes is preferred.

•  Ladybird and Dragonflies are helpful to get rid of aphids and mosquitoes.
•  Bacillus thuringiensis (Bt) is available in the form of sachets and is used to control butterfly caterpillars.
• These sachets are mixed with water and sprayed on vulnerable plants.
• Today with genetic engineering Bt toxic gene is introduced into the plants. Bt cotton is an example of such a plant.
• Trichoderma, a free-living fungi species, is an effective biocontrol agent.
• Baculoviruses are viruses that attack arthropods.
• They belong to the genus Nucleopolyhedrovirus.
• These viruses are widely used as they are species-specific and do not harm other valuable species.
• They have no negative impacts on other living organism and helps in the conservation of other species.

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Microbes as Biofertilizers

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With the increasing importance of environmental conservation, organic farming is becoming a common phenomenon. Organisms that enrich the soil with nutrients are known as biofertilisers. Six types of microbes in human welfare are used as biofertilizers these are: Rhizobium, Azotobacter, cyanobacteria, Azolla, and phosphate-solubilizing microbes.

• Rhizobium has a symbiotic relationship with the roots of leguminous plants and helps in fixing nitrogen.
• Azospirillum and Azotobacter are free-living bacteria that fix nitrogen of soil
• Mycorrhiza refers to fungi and plants that have a symbiotic relationship.
• They have a higher tolerance to salinity and drought and overall have a longer life span.
• Cyanobacteria are autotrophic bacteria and are essential biofertilisers in paddy fields which includes Anabaena and Nostoc.
• These bacteria also help in increasing organic matter in the soil.

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Things to Remember

• Microbes are microscopic organisms that cannot be seen with the human eye yet are all around us.
• Saccharomyces cerevisiae is also known as baker’s yeast.
• Enzymes are proteins that help in the speeding up of metabolism, or the chemical reactions that occur in our bodies. 
• Biogas is a mixture of gases that consist of methane, carbon dioxide and hydrogen.
• Microbes, particularly yeasts, were used to produce drinks such as wine, beer, whiskey, brandy, and rum.

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