Microbes in Human Welfare: Microbes play a very important role in human welfare and in the environment in many ways. Do you know how we make curd from milk? What do we use to make bread, butter and cheese? We use different types of microbes. Microbes or Microorganisms are tiny living organisms that are found all around us, i.e., in the water, soil, air and even inside our bodies. As they are very small to be seen by naked eyes, we use a microscope to observe them.

What are Microbes?

Microbes are tiny, unicellular (single-celled) living organisms that are invisible to the naked eye. The most common types are bacteria, viruses and fungi. The branch of science that deals with the study of different aspects of microorganisms is known as microbiology. Louis Pasteur is considered the Father of Modern Microbiology.

Use of Microbes in Human Welfare

Various microorganisms can tolerate extreme conditions like high salinity (halophiles), deep inside temperature (thermophiles) and in the highly acidic atmosphere (thermoacidophiles). It is possible to grow microbes in laboratories or at an industrial scale for research and production of various useful products. Some of the contributions of microbes to human welfare are discussed below:

1. Microbes in household products
2. Microbes in industrial products
3. Microbes in healthcare and medicine
4. Microbes as biofertilisers
5. Microbes as biocontrol agents
6. Microbes in sewage treatment
7. Microbes as biofuels

Let’s discuss these uses in further detail.

Microbes in Household Products

You’ll be amazed to know that we use microbes or products derived from them in many of our daily activities. Some of these are mentioned below:

1. A common example is the production of curd or yoghurt from milk. Microbes such as Lactobacillus and others commonly called lactic acid bacteria (LAB) are present in milk and convert it to curd. Lactobacillus is a microorganism that is the major part of the group of lactic acid bacteria which grows in milk and converts it into curd. This process increases the nutritional value of milk by increasing vitamin \({B_{12}}\).
2. The dough, which is used for making the famous South Indian delicacies such as dosa and idli, is also fermented by bacteria. The puffed-up appearance of dough is due to the production of \(C{O_2}\) gas during the process of fermentation.
3.  Similarly, the dough used for making bread is fermented using Baker’s yeast (Saccharomyces cerevisiae).
4. Toddy is one of the traditional drinks of some regions of southern India. It is made by fermenting sap from palms.
5. Cheese is also a product of fermentation, and varieties of cheese are produced due to different kinds of microbes used for fermenting. Different varieties of cheese are formed by using different microbes for fermentation. Some of them are given below:

Variety of Cheese	Microbe used for fermentation
Swiss Cheese	Propionibacterium shermanii
Roquefort cheese	Penicillium roqueforti
Camembert cheese	Penicillium camemberti
Parmesan Cheese	Lactobacillus casei, Lactobacillus helveticus

Have you seen large holes on a cheese block? How are they formed?
The large holes on cheese blocks are formed due to the production of large amounts of \(C{O_2}\) during the process of fermentation.

Microbes in Industrial Products

Microbes are also useful in industries to produce a number of products valuable to human beings. In Industries, microbes are cultured in very large vessels called fermentors. Many fermented beverages, antibiotics and chemicals are synthesised for commercial purposes.

1. Antibiotics: Antibiotics are chemical substances, which are produced by some microbes to kill or inhibit the growth of other (disease-causing) microbes. Antibiotics are considered one of the most significant discoveries of the 20th century and have greatly contributed to the welfare of human society. The first antibiotic produced was Penicillin discovered from the fungus Penicillium notatum by Alexander Fleming. Its full potential as an antibiotic was later found by Ernest Chain and Howard Florey. This antibiotic was used to treat wounded American soldiers in World War II. For this discovery, Fleming, Chain and Florey were awarded the Nobel Prize in \(1945\). After Penicillin, many other antibiotics were also extracted from microbes. Antibiotics have helped us to treat the deadliest diseases such as plague, whooping cough (Kali Khansi), Diphtheria, Leprosy, and a lot more.
Streptomyces, a genus of bacteria, which belongs to actinomycetes, produces several antibiotics like streptomycin, chloramphenicol/chloromycetin, tetracycline, terramycin, and erythromycin.

2. Fermented Beverages: Microbes, especially yeasts, have been used since ancient times for the production of beverages like wine, brandy, beer, whisky or rum. For this purpose, Saccharomyces cerevisiae, also called brewer’s yeast, is used for fermenting malted cereals and fruit juices, to produce ethanol. Varieties of alcoholic drinks are produced, depending on the raw materials used for fermentation and the type of processing (with or without distillation). Wine and beer are produced without distillation whereas whisky, brandy and rum are produced by distillation of the fermented broth.

3. Organic acids: Microbes produce various organic acids while performing various activities and functions. Some of them are given as follows:

Organic acid	Microbe
Citric acid	Aspergillus niger (a fungus)
Pectinases	Acetobacter aceti (a bacterium)
Butyric acid	Clostridium butylicum (a bacterium)
Lactic acid	Lactobacillus (a bacterium)

4. Enzymes: Enzymes are nothing but proteins that act as biological catalysts. In simple words, enzymes are proteins that speed up chemical reactions in the human body. Microbes are also used in the production of enzymes. A few of them are listed below:

Enzymes	Uses
Lipases	These are used in detergent formulations and are helpful in removing oily stains from the laundry
Pectinases	Bottled juices are clarified.
Streptokinase (produced by the bacterium Streptococcus)	These are used as a ‘clot buster’ for removing clots from the blood vessels of patients who have undergone myocardial infarction leading to a heart attack.

5. Other Bioactive molecules: Apart from organic acids and enzymes, there are many more bioactive molecules that are produced by microbial activities. Some of them are given as follows:

Bioactive Molecules	Microbes	Uses
Cyclosporin A	Trichoderma polysporum (a fungus)	Immunosuppressive agent in organ-transplant patients
Statins	Monascus purpureus	As blood-cholesterol lowering agents

Microbes in Healthcare and Medicine

Microbes also play a very important role in the field of healthcare and medicine. The branch of microbiology that deals with healthcare and medicine is called medical microbiology. Some of the use of microbes in healthcare and medicine is given as follows:

1. Production of Antibiotics
2. Production of Vaccines
3. Production of  Vitamins
4. Production of Antiseptics
5. Production of Human Hormones

Fig: Uses of Microbes in Healthcare and Medicine

Microbes as Biofertilisers

We are living in an era where environmental pollution is the major cause of concern. The use of excessive chemical fertilisers during agricultural activities has contributed significantly to pollution. To avoid the use of large quantities of chemical fertilisers, farmers are switching to organic farming and also they are using bio-fertilisers instead of chemical ones. Bio fertilisers are microbial inoculants that are used to enrich the nutrient quality of the soil. The main sources of bio fertilisers are fungi, bacteria and cyanobacteria. Below are some common fertilisers used in organic farming:

Microbes	Uses as a fertiliser
Rhizobium (Bacteria)	These are present in nodules on the roots of leguminous plants by the symbiotic association and fix atmospheric nitrogen into organic forms.
Azospirillum and Azotobacter (Bacteria)	They can fix the atmospheric nitrogen while livingly in the soil.
Fungi (mostly from genus Glomus)	It forms a symbiotic relationship ‘mycorrhiza’ with the roots of plants. It helps to absorb phosphorus from the soil and transport it to the upper parts. It provides resistance to root-borne pathogens, tolerance to salinity and drought, and an overall increase in plant growth and development.
Cyanobacteria (Anabaena, Nostoc, Oscillatoria, etc)	These are aquatic and photosynthetic. They can fix atmospheric nitrogen. They are important bio fertilisers in paddy fields.

Microbes as Biocontrol Agents

In simple words, biocontrol agents mean the different biological ways of controlling the growth of diseases or pests on plants which can be harmful. It helps in the protection of plants from their natural enemies like pests, weeds, nematodes, insects and mites, etc. Biocontrol agents are considered an integral part of organic farming. Some of the biocontrol agents used during organic farming are as follows:

1. Dried spores of Bacillus thuringiensis (often written as Bt) are mixed with water and are sprayed on vulnerable plants such as brassicas and fruit trees in order to control insect larvae. The ingested spores release toxins into the guts of larvae which kill them.
2. Biotechnology has developed many disease-resistant plants and pest-resistant plants by injecting toxic genes of B. thuringiensis into them. For example, Bt Cotton, Bt Brinjal, etc.
3. Fungus-like Trichoderma and baculoviruses of genus Nucleopolyhedrovirus are some other kinds of microbial biocontrol agents. They are used in the treatment of plant diseases and to kill insects.

Microbes in Sewage Treatment

The municipal wastewater that is generated every day in large quantities in towns and cities is called sewage water. A major component of this sewage water is human excreta. Sewage is treated in sewage treatment plants (STPs) by the heterotrophic microbes present in the sewage before being disposed of in water bodies.
The sewage treatment is divided into three steps, primary treatment, secondary treatment, and tertiary treatment.
There are various kinds of microbes used in sewage treatment. Among these, there are three types of microbes that play very important roles in the process.

1. Aerobic Microbes: These microbes are used in the secondary stage of sewage treatment, where the effluent from the primary stage is agitated in large aeration tanks causing the growth of aerobic microbes in flocs. This type of bacteria must have oxygen added mechanically for better results. These microbes consume the major organic matter in effluent resulting in a decrease in BOD (biochemical oxygen demand) of effluent.
2. Anaerobic Microbes: These microbes are used when the secondary sedimentation is done in sewage water treatment. The main function of anaerobic microbes in this stage is to reduce the sludge amount and create biogas (mainly methane) from it. They also remove phosphorus from the sewage water. The most common anaerobic forms belong to Actinomyces, Bifidobacterium, Clostridium, Propionibacterium and Peptostreptococcus genera.
3. Facultative: Facultative microbes in sewage treatment are bacteria that can change between aerobic and anaerobic depending on the environment where they are present. These bacteria normally prefer to be in aerobic conditions.

Microbes as Biofuels

Microbes can be used in the production of biofuels.

1. Ethanol: It is one of the most common biofuels produced from plants. The edible part of the plants, such as sugar cane, sugar beet or corn kernels, are used to make biofuels. The edible parts of those plants can be easily broken down into sugar (glucose). Then sugar is fermented (broken down) to ethanol by microbes such as the Baker’s yeast (Saccharomyces cerevisiae).
2. Biogas: The other most common biofuel which is used everywhere is biogas. Biogas is a mixture of different gases which are produced by the breakdown of organic matter in anaerobic conditions (in the absence of oxygen). It is primarily methane \(\left( {C{H_4}} \right)\), carbon dioxide \(\left( {C{O_2}} \right)\) and may have small amounts of hydrogen sulphide \(\left( {{H_2}S} \right)\). The gases methane, hydrogen and carbon monoxide \(\left( {CO} \right)\) can be combusted with oxygen which releases energy. This released energy allows biogas to be used as fuel. The bacterias used in biogas production are collectively called methanogens, and one such common bacterium is Methanobacterium. Methanogens are commonly found in the anaerobic sludge in sewage treatment; these are also present in the rumen (a part of the stomach) of cattle. Dung (animal excreta) can be used for generating biogas (also known as ‘Gobar Gas’).

Summary

Microbes or microorganisms play a very important role in human welfare. Not all microbes are pathogens; rather, these are useful to humans in many ways. We use products that are either microbes or derived from microbes in our day-to-day life. Lactic acid bacteria (LAB) is used to convert milk into curd. The dough of idli and bread is made by fermentation using Baker’s yeast or Saccharomyces cerevisiae.

The particular texture, taste and flavour of the cheese are due to the use of a variety of bacteria and fungi. Microbes are also used for the production of various industrial products like lactic acid, acetic acids and alcohol. Microbes are also used as bio fertilisers and biocontrol agents. They are also used to treat sewage water (wastewater). Methanogens are used to produce methane gas in biogas plants. Scientists are further researching the different ways in which we can use microbes in the welfare of human society.

FAQs

Q.1. What microbes are useful to humans?
Ans: There are several microbes useful to humans. For example, Lactic acid bacteria (LAB) are used to produce cheese, yoghurt, etc. Some of the other useful microbes are Saccharomyces cerevisiae, Aspergillus oryzae, L. plantarum, Thiobacillus ferrooxidans and Corynebacteria.

Q.2. Are microbes good or bad?
Ans: Microbes are good as well as bad. Good microbes are useful to humans in many ways. At the same time, the bad microbes are harmful pathogens that cause disease in humans, other animals and even plants.

Q.3. Why do we need microbes?
Ans: Our human body is the home of millions of microbes which helps our body to perform different processes. For example, they contribute to digestion, produce vitamin K, promote the development of the immune system, and detoxify harmful chemicals.

Q.4. Which microbes are used in medicine?
Ans: Streptomyces, which belongs to actinomycetes, produces several antibiotics like streptomycin, chloramphenicol/chloromycetin, tetracycline, terramycin, and erythromycin.

Q.5. How do microbes affect human health?
Ans: Different types of diseases are caused due to different types of disease-causing microbes (pathogens). Microbes may cause infectious diseases like flu, cholera, etc.

We hope this detailed article on Microbes in Human Welfare helps you in your preparation. If you get stuck do let us know in the comments section below and we will get back to you at the earliest.