Microorganisms and their advantages

CHAPTER –2 Microorganisms

Introduction

Organisms that are so small that they can only be seen through a microscope are called microorganisms or microbes.

The study of microorganisms is known as microbiology.

Most organisms are hardy and can be found in almost any kind of environment – hot desert, polar ice caps, salt water, marsh lands and inside other organisms.

Types of microorganisms:

There are five major groups of microorganism. These are as follows:

1.      Bacteria

2.      Algae

3.      Protozoa

4.      Fungi

5.      Viruses

Bacteria:   

· They are simple living organisms which are found all around us. They are mostly single- celled tiny organisms, but they live together in colonies of millions.

·       Bacteria are found in three different shapes:

1.      Rod shaped, called bacilli.

2.      Spherical shaped, called cocci.

3.      Spiral called spirilla. 

Algae:

·    Algae are simple plant- like organisms which are usually aquatic in nature.

     ·     They contain a cell wall and chlorophyll and can make their own food by photosynthesis.

·       Algae can be unicellular or multicellular.

·       Some of the common examples are diatoms, Chlamydomonas, and seaweed. Protozoa:

·       These are unicellular microscopic organisms similar to animals that can move about to capture food and are heterotrophic in nature.

·       They are mostly aquatic in nature.

·       Amoeba, paramecium are some examples of protozoa. Fungi:

·       Plant -like organisms that do not contain chlorophyll are called Fungi.

·     Fungi may be unicellular (Yeast) or multicellular (Bread mould) and are found in warm and moist places.

·   Fungi can be heterotrophic, saprophytic or parasitic in nutrition.

·   Examples: Yeast, Rhizopus (Bread mould), mushrooms, puffballs. Viruses:

·    Viruses are smaller than any known cell.

·       Viruses can only be seen with electron microscope.

      ·     Viruses can reproduce only inside the bodies of other organisms, which mean they need a host.

      ·  A virus is like a non- living thing outside the body of other organisms. Therefore, it is a borderline between a living and a non- living thing.

USEFUL MICROORGANISMS

Microorganisms are useful in the following ways:

 ·       In food and beverage industry

·       In making medicines and vaccines

·       In agriculture

·       In cleaning the environment

Food and beverage industry:

·  Bacteria help us in making certain foods. Lactobacillus is a bacterium that sours milk and is used to makes curd from milk.

·    Many fungi like Mushrooms and morels are edible which are rich

·       Yeast is commonly employed in preparing food items like bread, cakes, idli, dosa, dhokla etc.

·       Yeast is also used in breweries for making wines by the process of fermentation. 

Making medicines and vaccines:

·       Bacteria and fungi are used to make medicines called antibiotics.

·       The first antibiotic, penicillin was discovered by Alexander Flemming using the fungus penicillium.

·       Some common antibiotics are streptomycin and terramycin.

·       Microbes are used to make vaccines. Vaccines are weakened or dead germs introduced into the body. They offer protection against diseases like tuberculosis, polio etc. by producing anti- bodies.

·       Bacteria and Yeast are used in making vitamin B complex tablets.(Escherichia coli  survive in our intestine produces B-12)

·       The human hormonal called insulin can also be obtained from bacteria.

In Agriculture:

·       Some bacteria like Rhizobium, blue green algae like Nostoc, live in the root nodules of plants such as gram, pea etc. These bacteria absorb the nitrogen of the atmosphere and convert it into nitrate which serves as natural fertilizers for plants, hence, enhancing soil fertility.

In cleaning the environment:

·       Microbes help to keep our environment clean by decomposing dead matter. They decomposed substances are recycled as these get reused from the soil by plants.

·       Some bacteria decompose sewage and other waste in water. This is nature’s method of keeping the environment free from pollution.

HARMFUL MICROORGANISMS

     ·     Microorganisms that cause diseases in human, animals and plants are called pathogens or germs.

    ·       Germs may enter the body of living organisms through air, contaminated food and water, from an infected person by direct or indirect contact or by a carrier.

    ·       Diseases that can spread from an infected person to a healthy individual through air, water or direct contact are called communicable diseases. Examples: Common cold, chicken pox, AIDS etc.

·       Micro organisms also cause diseases in animals and plants. For examples-

·       Anthrax is a disease caused by bacterium and affects human and cattle.

·       A virus causes the dangerous foot and mouth disease in cattle.

·       Citrus canker is a bacterial disease that affects trees of citrus fruits and is spread by air.

·       Rust of wheat is a viral disease that affects vegetable like bhindi & spread by insects.

      ·     Malaria is actually caused by pathogen called plasmodium (protozoa) which is transmitted by female Anopheles mosquito.

·       Dengue is caused by dengue virus and spread by female Aedes mosquito.

Preventing the spread of Communicable diseases:

 Some simple methods of limiting the spread of communicable diseases are:

     ·       To keep the infected person separated from others & to advice his/ her to keep a handkerchief on the nose and mouth while sneezing.

·       To keep our environment or surrounding clean.

·       Never let garbage collect in the neighborhood.

·       Timely vaccination against diseases should also be taken.

     ·       To prevent mosquitoes from breeding we should not allow water to collect anywhere in our neighbourhoods.

Food spoilage:

 Many bacteria and fungi grow on food items and produce certain toxic substances. This makes the food unfit for consumption. Consuming such food can cause a serious illness called food poisoning.

Food preservation:

· Processing of food to prevent their spoilage and to retain their nutritive value for period is called food preservation.

·    Food can be preserved using many methods:-

  1.      Heating: heating food to a high temperature kills microbes. For example: Milk and water are boiled to kill microbes.

  2.      Cooling: food can be kept in refrigerator at about 5˚C which delays its spoilage.

  3.      Canning: canning is done to package or preserve food or drink by putting it in sealed, airtight containers.

  4.      Salting: Fruit and vegetables can be preserved by using salt and then drying. Salts prevent the growth of microbes.

  5.      Sweetening: Excess sugar can also works on the same principle as salting. Jams, jellies & squashes are preserved by this method.

  6.     Dry or dehydration: Dehydration of food remaining water from it. This stops microorganisms from growing as they cannot grow without water.

 7. Chemical preservatives: Chemicals like sodium benzoate and sodium meta-bisulphite prevent microbial attack and are often use to preserve jams, sauces & ketchup.

Nitrogen cycle :-

The nitrogen in the atmosphere is converted into nitrogen compounds in the soil by

nitrogen fixing bacteria and  blue green algae. Lightning also converted into nitrogen

compounds in the soil. The nitrogen compounds in the soil is used by plants for the synthesis

of proteins and other compounds. Animals feeding on plants get these proteins and other

compounds. When plants and animals die, bacteria and fungi in the soil converts the

nitrogenous waste into nitrogen compounds in the soil which are again use by plants.

Some other bacteria converts some nitrogen compounds in the soil into nitrogen gas which

goes back into the atmosphere. Hence the nitrogen in the atmosphere almost remains constant

 

Natural Gas

Occurrence- Natural gas is found along with petroleum in reservoirs under the ground. Composition- It is chiefly made up of methane, though butane and propane are also present in small proportions. 

Advantages

1) It is a clean non-polluting fuel. 

2) It can be easily transported through pipes. 

3) It can be pressed and stored under high pressure as compressed natural gas (CNG). 

Uses

1) CNG is used for power generation. 

2) In some parts of India, e.g. Vadodara, CNG is supplied to homes and factories through pipes and directly used as a fuel. 

3) CNG is also now being used as a non-polluting fuel for vehicles. 

4) Natural gas is used as a starting material for the manufacture of chemicals and fertilizers. 

Natural gas is a fossil fuel found naturally as a hydrocarbon gas mixture in the oil wells. Its main component is methane but it may also contain varying amounts of other higher alkanes (a group of elements). Gases like carbon dioxide, helium, nitrogen, and hydrogen sulphide are also found in natural gas in small percentages.

Why is Natural Gas important as a fossil fuel?

·  Natural gas is considered important as this fossil fuel can easily be transported through pipes.

·   It is stored as CNG which is used for several purposes and is also used as a starting material for manufacturing many chemicals and fertilisers.

·    Natural Gas does not cause pollution and has high calorific value. Compressed Natural Gas (CNG) is the natural gas stored under high pressure.

Why is CNG useful? CNG is used as:

·     Fuel to generate power

·    Cleaner fuel for transport vehicles (less polluting than petrol and diesel)

·    Fuel in homes and industries which can be supplied through pipes.

·       CNG pipeline network already exists in Vadodara in Gujarat, some parts of Delhi and some other places.

Why is CNG considered as a cleaner fuel?

·       Natural gas is considered a better fuel than coal and petroleum because it is cleaner.

·       This means that it results in less amount of pollution that the other fossil fuels.

·    Natural gas emits 50% less carbon dioxide, sulphur and nitrogen oxides in the air.

·    However, it is not the best solution as there are better sources of energy present nowadays like solar energy.

In India, vast reserves of natural gas are found in: Maharashtra, Rajasthan, Tripura, and River Delta of Krishna and Godavari.

Some Natural Resources are Limited

Fossil fuels, such as coal, petroleum, and natural gas cannot be created in the laboratory as it is not possible to create the natural conditions under which they are formed. Moreover, it takes thousands of years for them to be formed.

Consequences of the burning of fossil fuels

1.  Increase in air pollution: The burning of fossil fuels results in the release of unburnt carbon particles in the air. These particles act as pollutants and increase

air pollution. Fossil fuels release poisonous gases such as carbon monoxide and sulphur dioxide in the atmosphere.

2.  Global Warming: Fossil fuels when burnt release large amounts of carbon dioxide in the air. As the amount of carbon dioxide increases it results in an increase in the global temperature of the earth and leads to global warming.

Why should we use fossil fuels economically?

1.    They are available in limited quantities.

2.    Burning these fuels also cause air pollution as well as global warming.

Hence, we should use these fuels economically to make sure that we can use them for a longer time, the risk of global warming gets reduced, and we can live in a cleaner environment.

How can we save petrol or diesel while driving?

According to the Petroleum Conservation Research Association (PCRA) in India, we can save petrol or diesel while driving by:

1.    Drive at a constant and moderate speed.

2.    Maintain tyre pressure at correct levels.

3.    Switch off the engine when you are waiting( such as traffic light).

4.    Do regular maintenance of your vehicle.

Why fossil fuels can last for 100 years only?

·       Fossil fuels are exhaustible resources which mean that they are not present in abundant quantities on the earth.

·    They take hundreds and thousands of years to replenish.

·  The rate at which they are being consumed today is increasing at a rapid pace.

·   It means that more amounts of fossil fuels are being used than it is being replenished.

·    Hence, scientists claim that they can replenish completely in 100 years.

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