Advantage and disadvantages of microorganisms

Advantages of microorganisms:- 1). They are used in wine making , baking , and other food making process. 2). Alcoholic fermentation by yeast is widely used in the preparation of wine and bread . A bacterium Lactobacillus , promotes of curd . 3). Yeast reproduces rapidly and produces carbon dioxide during respiration . Bubbles of the gas fill the dough and increases it's volume . 4). Microbes are used to reduce pollution . For example, decomposers such as bacteria and fungi break down dead bodies and excreta to form inorganic compounds , which can be absorbed by plants . 5). They are used to increase the soil fertility by fixing the atmospheric nitrogen with the help of bacterium Rhizombium and some other blue - green algae . 6). Microbes also play an important role in the preparation of medicines . 7). Antibiotics are chemicals produced by micro - organisms to kill bacteria . Streptomycin , for example is an antibiotic. 8). Certain microbes are also used in the biological treatment of sewage and industrial effluents. 9). Antibiotics are used to control many plants diseases. 10). Antibiotics are mixed with the feed of livestock and poultry to check microbes inflection in animals . Disadvantages of microorganisms :- 1). Micro - organisms cause diseases in animals . For ex. in humans , bacteria cause diseases such as tuberculosis , cholera , typhoid . 2). In cattle the foot and mouth disease is caused by a virus . 3). Also , several microbes cause diseases in plants . For example the productivity of wheat , orange , apple , etc. is reduced due to microbial diseases in plants. 4). Certain microbes , entering into our body , produce toxic substances . This leads to food poisoning . Some micro - organisms such as fungus spoil our food . For example , bread when left unused under moist conditions gets spolit by fungus , producing a white - cotton - like growth on the bread .

Harmful Microorganisms:

Microorganisms can be harmful in many ways. For example – some of the microorganisms cause diseases in human beings, other animals and plants. Such microorganisms which cause diseases are called pathogens.

1. Disease causing Microorganisms in Humans:

Pathogens enter our body through the air we breathe, the water we drink or the food we eat. They can also get transmitted by direct contact with an

infected person or carried through an animal. Microbial diseases that can spread from an infected person to a healthy person through air, water, food or physical contact are called communicable diseases. Examples of such diseases include cholera, common cold, chicken pox and tuberculosis.

The communicable diseases can occur and spread in the following ways:

1. By breathing of air containing microorganisms.
2. By taking infected food and water.
3. Through insect bites.
4. By sharing infected injection needles.
5. By physical contact with an infected person.For example – common cold disease spreads by breathing air containing microorganisms.

The beneficial effects of microorganisms in detail:

1. Making of Curd and Bread: Lactobacillus bacterium present in milk promotes the formation of curd. It multiplies in milk and converts it into curd. Bacteria are also involved in the making of cheese, pickles and many other food items. Yeast is used in the baking industry for making bread. When yeast is mixed in dough for making bread, the yeast reproduces rapidly and gives out carbon dioxide gas during respiration. The bubbles of the carbon dioxide gas fill the dough and increase its volume. This makes the bread rise and light, soft and spongy.

 

1. Commercial Use Of Microorganisms: Microorganisms are used for a large scale production of alcohol and acetic acid. Yeast is used in making alcohol and wine because it is capable of converting sugar into alcohol. The sugar for making alcohol comes from the substances such as cane juice and fruit juices, or from substances like barley, maize, rice, etc. The process of conversion of sugar into alcohol by the action of yeast is called fermentation. Louis Pasteur discovered the process of fermentation in 1857.

 

1. Medicinal Use of Microorganisms: A medicine which stops the growth of, or kills the disease-causing microorganisms is called an antibiotic. The source of antibiotic medicines are microorganisms. These days a large number of antibiotics are produced from microorganisms such as fungi and bacteria. Some of the common antibiotics which are made from fungi and bacteria are Penicillin, Streptomycein, Erythromycein and Tetracycline. Antibiotics kill the disease-causing microorganisms but usually do not damage human body cells. The first antibiotic ‘penicillin’ was discovered by Alexander Fleming by chance in 1929, and was extracted from the tiny fungus called ‘Penicillium’. Antibiotics are used to treat many bacterial diseases in humans but are not effective against the diseases caused by viruses. They can be used to treat many diseases in animals. They are mixed with the feed of live stock and poultry birds to control microbial diseases in animals. Antibiotics are also used to control many plant diseases.

 

1. Vaccine: Microorganisms are used to make vaccines to provide immunity against a particular disease. A vaccine contains the dead or weakened but alive microorganisms of a disease.  When the vaccine is introduced into the body of a healthy person orally or by injection, the body of that person responds by producing some substances called antibodies in the blood. The antibodies remain in the blood of the person for a long time and fight against the same microorganisms and kill them if they happen to enter the body naturally or later date. This is how a vaccine works.  Thus, a vaccine develops the immunity from a disease.  Several diseases can be prevented by vaccination including cholera, polio, tetanus, measles, rabies, diphtheria, tuberculosis, smallpox and hepatitis. Edward Jenner discovered the vaccine for smallpox in 1798.

 

v. Increasing Soil Fertility: Some of the microorganisms present in the soil can fix nitrogen gas from the atmosphere to form nitrogen compounds. These nitrogen compounds mix with the soil and increase the fertility of the soil. Example – some bacteria and blue-green algae. Such microbes are commonly called as biological nitrogen fixers.