Bacteria are viewed as only harmful to humans. But they have very great role in human life.
Besides, they also play a great role in the ecological stability and the environment.
The bacteria are the most robust unicellular organisms.
They can survive even in the adverse conditions like extreme temperatures (high or low), starvation, droughts etc.
They can do this because of their ability to reproduce faster, transform into metabolically inert yet live forms.
These inert forms are called spores which rupture to give out bacteria when suitable conditions arise. Bacteria are the boon to the environment and without them surroundings around us could not have been clean and tidy.
They are also of vital importance to humans, plants and animals.
In many ways they contribute to Human health, in terms of body physiology, metabolism and excretion.
Importance of bacteria for environment:
♠ Natural scavengers: Bacteria are the natural scavengers on the earth. They decay any dead and waste matter on the surface of the earth and in the soil.
Hence there is no accumulation of dead corpse of animals over so long years of emergence of life on earth.
This degraded and decomposed substance ads to fertility of plants or converts to bio gas.
♠ Further they degrade any chemical or biochemical fallen on the soil and there by detoxify the valuable soil. Thus they make it fit for growth of plants & animal safe survival on the earth. Even the vast amount of chemical and other waste are degraded over a period of weeks in the water. Or else the soil and water would be toxic for further use.
♠ Nutrition: They are important source of vegetative nutrition in marine environment. They provide major & micro-nutrients required for sustenance of marine animals. i.e. they form the starting point of marine food chain.
Importance of bacteria for plants:
As a source of manure (fertilizer enhancers).
♦ Bacteria are helpful for plants. They render the soil suitable for growth of plants. They breakdown any dead and organic matter into humus so that the plants receive essential mineral elements for growth.
♦ Ammonifying bacteria which converts proteins, amino acids and nucleic acids of dead bodies into ammonia. Ex: Bacillus.
♦ Nitrifying bacteria: Ammonia is also oxidized to nitrates by nitrifying bacteria. Ex: Nitrosomona, nitorbacter.
Importance of bacteria for animals:
• Bacteria like Entero-coli live in the gut intestines of animals in symbiotic fashion. They are friendly bacteria helping in degradation of unused food and help in its expulsion from body.
• Some bacteria like E.coli which are present in the body resist growth of harmful bacteria like typhoid.
Medical Importance of bacteria
There are many human friendly bacteria in the body. Without them, body would be susceptible to harmful infection.
* For antibiotic production: Antibiotics were found to be produced by bacteria and these antibiotics could rescue people form other harmful and pathogenic bacteria. Initially most antibiotics were produced by fermenting large cultures of bacteria. Now synthetic ones are in large supply.
* For production of vaccines: Bacteria are used to produce vaccines by either separating their antigens or sometimes dead form or else even live one with lack of pathogenic character.
Ex: TB-vaccine is one where dead bacteria of TB are administered to build up resistance to tuberculosis in humans. Once administered, these bacteria cannot cause disease. But the body will be able to produce antibodies to kill any infection of mycobacterium.
Probiotics: Bacteria are also part of probiotics. These are friendly bacteria which can be used to fight infections. They are specially used to treat diarrhea in children.
* For genetic engineering: Bacteria have short reproduction cycles. Some of them can divide in minutest o produce new daughter cells. This factor of bacteria is used in biotechnology to produce biological compounds. Products like insulin, vitamin-B12, etc. are supplied in large scale in continuous basis due to their manufacture using genetically modified bacterial cells.
For an idea check → rDNA technology applications.
Importance of bacteria in agriculture
Bacteria play a vital role in agriculture for disease prevention and enhance the fertility.
1. Bio-pesticides: They act as bio-pesticides to kill disease causing diseases to crops and aid in higher yield.
Ex: Bacillus thuringiensis is one example of pesticide to kill pests. Some species of bacillus, pseudomonas act as anti-fungals.
These bacteria are such that when applied they kill only the disease causing pests and insects. But they do not harm the plant or farmer. Because they are specifically harmful to pests.
Further they are not harmful to the soil unlike chemical fertilizers. Chemical fertilizers pollute the soil, air and water around. But use of bio pesticides avoids this problem. Further they are less expensive.
2. Organic manure: Composting is a way to make natural manure. This manure imparts fertility to soil.
Some farmers even make their own organic compost by use of kitchen and other vegetable waste. This waste is allowed to decompose in presence of moisture, air, carbon and nitrogen ingredients.
check out organic composting.
3. Bio fertilizers: When bacteria like blue-green algae are left into agriculture soil, they fix natural manure in the form of nitrogen from air for better growth and yield of crops.
Also when a crop is harvested, the plant remains are allowed to degrade in the soil. Under rainfall, this waste material is acted on bacteria to decompose it. This organic material acts to increase water retention capacity of the soil. Further the the organic waste acts as natural manure and gives essential nutrients to the next crop.
Further these bacteria play role in nitrogen fixation.
Importance of Bacteria in nitrogen cycle
1. Fix nitrogen in soil: Bacteria like chlorella are used as green manures to increase soil fertility. There absorb nitrogen from air and fix it in the soil. Thus the nitrogen content of the soil increase and provides fertility to crops. Ex: cyanobacteria.
2. Crop rotation: Farmers cannot grow the same crop year after year. If they do so, the yield of crop drops and also the subsequent crops are affected by pests and diseases. To avoid this, the farmers opt for crop rotation. This crop rotation is done by alternating crops with a leguminous crop. For example a farmer growing cotton this year will opt for leguminous crop like ground nut or peanut the next year. This not only destroys the pests of previous crop but also builds fertility. This rise in fertility due to leguminous crop is due to the presence of symbiotic bacteria in the roots.
The rhizobium is an example of such bacteria. This bacteria resides in the nodes of the roots of leguminous plants and helps absorb nitrogen from air and fix it in the roots. In-turn these bacteria extract nutrition from the plant (symbiosis). Thus bacteria help the plant and also build fertility in the soil.
Importance of bacteria for industry
Bacteria are also useful for industrial & commercial purposes
♠ Fiber industry: Bacteria like clostridium butyrcum is used in retting of flax, sunhemp to extract clear fiber.
♠ Tea and tobacco: Micrococcus and Bacillus megatherium are used in curing of tea and tobacco.
♠ For beverage industry: For this industry bacteria contribute in fermentation of wine used as beverages to form alcohol.
♠ Dairy industry: In dairy industry and homes ferments milk to produce curd.
♠ Sterilization: This is a process to eradicate microbial contamination from finished products. Few bacteria are used as biological indicators for sterilization validation. These bacteria are available commercially as strips containing spores.
Economic importance of bacteria
Bacteria are sold in different forms as seen before like
a. Medicine (probiotcs), antibiotics, insulin and other medicines are obtained from them.
b. Agriculture as bio-pesticides and fertilizers. In-fact this is a big industry and makes a lot of money.
c. In making beverages and fibers.
Thus bacteria are of great economic importance to humans, animals and the environment around.