Many investigators after a lot of hard work have been able to establish the multifold uses of bacteria in the field of Biotechnology, which has established bacterial use as a tool of economic importance.
Its multi-dimensional uses can be divided into two major subdivisions on the basis of its effect on human life.
We will be discussing all those uses of bacteria that help us. This can be further divided into the fields of Agriculture and Industry.
The Economic Importance of Bacteria In Agriculture
Many species of saprophytic and symbiotic bacteria add to the fertility of the soil and develops Rhizophere providing the Nitrogen and Sulphur cycle more effectively.
Bacteria of various kinds are associated with the leaves, stems, flowers, seeds, and roots of the plants. They influence the plants in many ways. The plants release a wide range of potential microbial substrates, inhibitors, and stimulants.
The soil bacterial population responds to the release of organic material in the immediate vicinity of the bacterial community, this region is called the rhizosphere and is very important to the soil with low fertility.
In the rhizosphere, nitrogen fixation performed by Azotobacter and Azospirillum increases ammonium ion availability for the plants. Rhizobium, a prominent member of the Rhizosphere community can fix nitrogen.
B) Nitrogen Cycle in Agriculture | Ammonifying and Nitrifying Bacteria
Bacillus subtilis, B. mycoides, B. ramosus, etc., act upon the dead animals and decompose their complex organic compounds like proteins into ammonium compounds. They are also known as putrefying bacteria.
Nitrosomonas oxidize the ammonium compound into nitrites in presence of free oxygen and Nitrobacter oxidize nitrites into nitrates in the presence of free oxygen. Thus, ammonifying and nitrifying bacteria increase the number of nitrogenous compounds in the soil. Dead plants, animals, etc., are converted into humus, which itself acts as fertilizer for the plants.
Nitrogen Fixing Bacteria
Azotobacter, Clostridium, and Rhizobium fix free nitrogen in the soil and make it available to the nitrogenous compounds in the soil.
The third one is a symbiotic type. They take the free atmospheric nitrogen as they live in the root nodules of leguminous plants and fix it within their tissues.
These bacteria help plants grow in the soil having no other source of nitrogen. The leguminous plants make the soil rich in nitrogen supply and thus are used as green manure.
Mechanism Of Nitrogen Fixation
The mechanism of nitrogen fixation takes place with help of the special types of bacteria, which fixes free atmospheric nitrogen gas into ammonia by means of symbiosis with leguminous plants.
One of the bacteria taking part in the process includes Rhizobium leguminosarum, which is a soil-born bacterium. They produce IAA (Indol Acetic Acid), which affects the root hair and made them curl.
These rod-like bacteria penetrate through the tip of the root hair forming a continuous infection thread that enters the cortical region within twenty-four hours.
During its passage through the root hair, the infectious thread gets surrounded by the cellulose wall. The host as a reaction to the infection secretes this wall.
The infectious thread ramifies in the cortical region and the bacterial rods are released in the cytoplasm of the cells, which are stimulated. These cells are enlarged and multiply to form the characteristic nodules all over the root system.
On the outer side, the root nodule has a cortical layer which is followed by an actively proliferating region, then the vascular system encloses in the center a zone of bacteria.
These bacteria absorb the atmospheric nitrogen and make it available to the host plant in the form of ammonia, which is being convened into nitrates.
In turn, they get shelter and nutrients in the form of carbohydrates from the plant. On the death and decay of the plant, the bacteria are set free to attack the new plants and thus add to the fertility of the soil.
The fixation of free nitrogen from the atmosphere through ammonia into free nitrates and again, their conversion into ammonia and free nitrogen takes place by means of nitrifying and denitrifying bacteria, along with other organisms. This process is known as the nitrogen cycle.
C) Sulphur Cycle | Describe Sulphur Cycle And Role Of Bacteria In It
Bacteria contribute greatly to the Sulphur cycle. Photosynthetic bacteria transform Sulphur by using sulfide as an electron source. In the absence of light, sulfide can be used by Thiobacillus and other lithoautotropic.
In contrast, sulfate can undergo sulfate reduction when organic reductants are present; Desulfovibrio can derive energy by using sulfate as an oxidant under these conditions.
Dissimilatory reduction occurs when sulfate is used as an external electron acceptor. (anaerobic respiration) to form sulfide.
In comparison, the reduction of sulfate for amino acid and protein biosynthesis is described as assimilatory reduction.
When pH and oxidation-reduction conditions are favorable, several key transformations in the sulfur cycle also occur as a result of the chemical reactions.
The Economic Importance Of Bacteria In Industry
Human understanding of bacterial metabolism made him employ different bacteria for the manufacture of different industrial products.
Importance Of Bacteria In Food Production
Butter Making Industry
Saprophytic bacteria such as Lactobacilli popularly known as starters make the milk sour and produce various flavors. They are employed in the butter industry for ripening milk and producing flavor in butter.
Cheese Making Industry
Bacteria are also employed in the cheese industry. The casein of milk is ripened by certain bacteria after its coagulation process. Bacteria helps in making the casein spongy, and soft and give it a characteristic taste and flavor.
Vinegar Making Industry
The vinegar industry depends on the working of the bacteria Bacillus aceti, which converts the sugar solution into vinegar.
Alcohol And Acetone Manufacturer
Butyl alcohol and acetone are manufactured by the action of bacteria on molasses.
Bacteria are utilized in both processes of curing and ripening raw crud dry leaves of tobacco. These leaves are passed through the curing and ripening process before they are ready for use. Due to bacterial activity, the tobacco obtains a peculiar taste and smell.
Fresh crud leaves of tea are subjected to fermentation with the help of bacteria. The process is known as curing, which is employed to impart a peculiar taste and flavor to the tea, which is due to bacterial activity.
The process of preserving green fodder in pits is known as Ensilage. Certain bacteria help in the process of preservation of fodder.
Importance Of Bacteria In Medicine
Those chemical substances which are produced in the host tissues in response to the attack of parasitic bacteria are called Antitoxins.
Different vaccines and serums are now prepared from these are used in the treatments of specific ailments. The antibiotics such as streptomycin, aureomycin, etc., are obtained from certain actinomycetous bacteria.
Antibiotics Against Gram Positive and Gram Negative
In the medicine field, many questions arise about the use of bacteria and one of the questions is; “what antibiotics are used to treat gram-negative bacteria”.
The answer is that there are different antibiotics made for both gram-negative and gram-positive bacteria.
Which Antibiotics Treat Gram Negative Bacteria?
Trimethoprim-sulfamethoxazole, Imipenem, Cephalosporins (ceftriaxone-cefotaxime, ceftazidime), Broad-spectrum penicillins with or without β-lactamase inhibitors (amoxicillin-clavulanic acid, piperacillin-tazobactam).
Which Antibiotics Treat Gram-Positive Bacteria?
Erythromycin, Vancomycin, Lincomycin, Cloxacillin, Penicillins, Clindamycin, Fusidic Acid.
Importance Of Bacteria In Other Industries
What Is Tanning
In leather tanning, the hides and skins after drying salting, and cleaning are steeped in fluids containing specific bacteria. The process of fermentation goes on for some time aid then they are transferred to tan pits and further allowed to be fermented. This whole process is known as tanning.
The procedure of separation of fibers from the plant tissues is called Retting. Bacteria are employed in this industry, which causes decay of the softer tissues and renders fiber easily separable mechanically.
Coconut, jute, flax, hemp, and other fibrous plant fibers are obtained by an immersion process. This involves the dipping of specific plant organs in stagnant pond water where bacteria develop and cause retting.
The Sewage Work
In order to overcome solid and semisolid sewage waste, it is allowed to be putrefy. Putrefying bacteria are allowed to act upon sewage under anaerobic conditions. It gets decay and liquefied. It is filtered and the liquid is either drained into the river or used as manure in the fields.
Harmful Effects Of Bacteria
Besides their role as beneficial agents, they are also harmful roles to perform. Many bacteria are found to perform a harmful role to human beings thus they need attention.
Bacteria cause a lot of losses to animals including man and plants causing various diseases. The prominent human disease includes typhoid, pneumonia, dysentery, tuberculosis, tetanus, etc., while plant disease includes ring disease of potato, yellowing rot of wheat, citrus canker, etc.
Antibiotics Resistance In Bacteria
Sometimes the antibiotics don’t work because of the antibiotic resistance of bacteria that they develop over time. That’s why bacteria become stronger and more dangerous to human health and a cause of a great number of diseases in humans and animals.
Human food is also a consumable item for bacteria. Thus, the food is spoiled causing decay it can be prevented by fixing free water with the addition of salt, sugar, and oil.
Loss Of Soil Fertility
Anaerobic bacteria such as Bacillus denitrificans reduce the nitrates of poorly aerated soil to nitrates and then to ammonia compounds. Free nitrogen thus produced is liberated from the soil, rendering the soil nitrogen-free and thus less fertile.