Economic Importance of Bacteria- Useful & Harmful Activities

Economic Importance of Bacteria

· Bacteria are single-celled microscopic organisms, living in different types of environment and surviving in extreme conditions. They play significant role in day to day activities of human beings.

· Bacteria cause many harmful effects, including diseases in man, animals and plants. At the same time, they show many beneficial effects. Hence, they are our ‘friends and foes’ simultaneously. In this post we will discuss about the Economic Importance of Bacteria- Useful & Harmful Activities of the bacteria.


Beneficial Activities of Bacteria

Role of Bacteria in Agriculture

Decay and decomposition of organic matter

· They cause decay and decomposition of dead plants and animals, which is important for mineral cycling.

Nitrogen cycle

· The proteins in the dead bodies of living organisms are converted into amino acids then into ammonia by ammonifying bacteria (Bacillus vulgaris).

· Further, Nitrifying bacteria convert it first into nitrates (Nitrosomonas, Nitrococcus) which are finally converted into nitrates (Nitrobacter). In presence of denitrifying bacteria (Pseudomonas denitrificans), nitrates and nitrites in soil are converted to gaseous nitrogen.

Nitrogen fixation

· The biological process of nitrogen gas getting converted into nitrogenous compounds in presence of nitrogen fixing bacteria is called as nitrogen fixing bacteria.

· For Eg – free living bacteria are Azotobacter (aerobic) and Clostridium (anaerobic).Common symbiotic bacteria are Rhizobium leguminosarum and Xanthomonas.

Manure preparation

· Saprophytic bacteria prepare farmyard manure by converting farm wastes, dung and other organic wastes into humus.


Role of Bacteria in Industry

Role of Bacteria in Dairy Industry

· Man has utilized the metabolic activities of bacteria in various industrial products like Butter milk and sour cream, Yoghurt, Cheese etc.

· Lactic acid bacteria (LAB) play an important role in the fermentation process in the dairy industry. Some lactic acid bacteria (LAB)  such as Streptococcus lactis, Lactococcus lactis, Lactobacillus casei, Lactobacillus acidophilus, Lactobacillus bulgaricus, etc. are used to produce butter, cheese, curd, etc.  These bacteria ferment the lactose in the milk to produce lactic acid, which helps in curd coagulation and texture formation during the cheese production.

Role of Bacteria in the Vinegar industry

· Acetic acid bacteria (AAB) are used in the vinegar industry for the production of certain foods and vinegar.

· They can produce acetic acid during oxidative fermentation by performing oxidation reaction producing vinegar as a byproduct. Eg. – Acetobacter aceti, A. cerevisiae etc.

Retting of fibres

· Retting is process where a microbial population decompose fibres in order to separate them. The tissues are dipped in water tanks full of anaerobic butyric acid bacteria that dissolve the pectin of cells, thus, separating the fibres. Bacillus subtilis, Clostridium and Pseudomonas pseudomallei are bacteria used.

Curing of leaves

· The tastes and flavour in tea is improved using Micrococcus candisans and in tobacco leaves by Bacillus megatherium.

Single cell proteins (SCP)

· These are protein supplements used for treatment. Eg, – Methylophilus, methylotropus and Rhodopseudomonas capsulate.

Role of Bacteria in Butanol and Acetone Production

· Butanol or butyl alcohol (C4H9OH) and acetone or propanone [(CH3)2CO] are produced by using bacteria in a different industry. 

· In this case, Clostridium acetobutylicum is the most well-known and widely used species for the production of Butanol and acetone as a commercial basis.  Clostridium beijerinckii is also used to produce Butanol and acetone with excellent results.

Tobacco industry

· Bacillus megatherium is used for its fermentative capacity for developing flavour and taste in tobacco leaves.

Tanning of leather

· Some bacteria decompose fats which are found in skin of animal with the result that skin and hairs are separated from each other and this leather becomes ready for use.

Role of Bacteria in Medicine

· Bacteria have a major role in preparation of medicinal products like antibiotics, vaccines, serums and vitamins. Thus proving Economic Importance of Bacteria in human welfare.


· These are the chemical substances produces by living microorganisms capable of inhibiting or destroying other microbes.

· These are the products of secondary and minor metabolic pathways, mostly secreted extracellularly by the microorganisms. These are used in controlling various infectious diseases.

· The organic substances produced by microorganisms that does not allow other organisms (mostly pathogens) to grow are called antibiotics. Some antibiotics produced by bacteria are –



Obtained From


Bacillus lichenifomis


S. aurefaciens


Aerobacillus polymyxa


B. brevis


B. subtilis


Streptomyces griseus


S. venezuelae


Vaccine production

· Vaccine and serums are prepared from the whole or part of bacteria or their toxins.

· They are against typhoid, cholera TB, pertussis, tetanus and diphtheria Eg – DPT (against diphtheria, pertussis and tetanus), TT (against tetanus), BCG (Bacille of Calmette-Gurein against TB), DT (against diphtheria and tetanus).


· Several bacteria are used in industrial production of a various vitamins. Different probiotic bacteria have several health benefits, including vitamin production.

· They are able to synthesize vitamin K and B vitamins, such as biotin, nicotinic acid, cobalamin (Vitamin B12), panthotenic acid, folates, pyridoxine, riboflavin (Vitamin B2), and thiamine, etc.

· Eg. – Lactococcus lactis, Pseudomonas denitrificans, Clostridium butylicum etc.



Obtained From


Clostridium butylicum

Cobalamine (B12)

Bacillus magnatherium and Pseudomonas denitrificans

B-complex vitamins and vitamin K

Escherichia coli from the human intestine


Role of Bacteria in Pollution control

· Pseudomonas putida degrades petroleum wastes. Flavobacterium can decompose 2, 4-DDT.

· Gange’s water contains Bdellovibrio bacteriovorus that maintains purity of its water.

· Poly-hydroxybutyrate is used to produce biodegradable plastic.

Role of Bacteria in the Degradation of Petroleum

· Hydrocarbon contamination is one of the major environmental problems, occurs due to the accidental releases of petroleum products from the petrochemical industry, oil tankers, ships, etc.

· The ultimate natural mechanism is the microbial degradation which can clean up the pollutants of petroleum hydrocarbon from the environment proving Economic Importance of Bacteria.

· Eg. – Pseudomonas fluorescens, P. aeruginosa, Bacillus subtilis, Alcaligenes sp. etc.

Sewage disposal

· The bacteria decomposes the sewage organic matter, converting into simpler inorganic substances that pass out through filter. This liquid is useful for irrigation purposes, Eg. – Clostridium, E. coli.


Harmful Activities of Bacteria

Role of Bacteria in Food Spoilage

· Under favourable temperature and conditions, bacteria grow in food materials and cause decay of food, i.e., they alter their normal form and induce unpleasant aroma, taste and appearance. Some bacteria produce powerful toxins in food to cause ‘food poisoning’.

· By consuming those foods, different types of diseases such as gastroenteritis, dysentery, etc. can occur, even causing death.

· Sometimes foods are poisoned by the bacteria like Streptococcus aureus and Clostridium botulinum.

· Some examples of bacterial food spoilage are –

o Streptococcus, Micrococcus and Lactobacillus also can cause decay of milk and different milk products.  Greening on meat surface is caused by Lactobacillus.

o Souring of milk is caused by Lactobacillus and Streptococcus.

o Micrococcus can cause vegetable spoilage.

· Botulism – It is caused by Clostridium botulinum. The main symptoms are vomiting followed by paralysis and death.

Role of Bacteria in Water Pollution

· Water is polluted by different bacteria which make it inappropriate for drinking.

· Polluted water can cause diseases like cholera (Vibrio cholera), typhoid (Salmonella typhi) and bacillus dysentery (Shigella dysenteriae). These are eliminated by chlorination.

Role of Bacteria in the Reduction of Soil Fertility

· Moist soil inhabiting bacteria are capable of transforming soil nitrates into gaseous nitrogen. This process is called denitrification, and those bacteria are called denitrifying bacteria.

· By the process of denitrification, the following bacteria such as Pseudomonas, Micrococcus, Thiobacillus etc. convert nitrates of the land into gaseous nitrogen; as a result, a good loss of nitrogen occurs from the soil causing reduction of soil fertility.

Role of Bacteria as Biological warfare

· Some bacteria which cause diseases like anthrax, black-leg, tuberculosis etc. are employed as secret war agents.

Role of Bacteria as Disease Causing Agents

· Many parasitic bacteria induce diseases in plants and animals, including human. A list of pathogenic bacteria, respective diseases and their site of infection are shown in the following table –


Bacteria causing Diseases in Humans

Name of Bacteria


Site of Infection

Salmonella typhi


Alimentary canal

Bacillus dysenteriae


Intestinal tract

Vibrio cholerae


Intestinal tract



Intestinal tract

Leptospina hemorrahagiae



Mycobacterium tuberculosis



Diplococcus pneumonia



Bordetella pertussis

Whooping cough (pertussis)

respiratory tract

Streptococcus pyrogenes



Corynobacterium diptheriae



Clostridium tetani


Blood vascular system of man

Streptococcus sp.


Joints tendons, ligaments, bones

Mycobacterium leprae



Nesseria gonorrhoea


Urethra, rectum

Treponema pallidum


genitals, rectum or mouth

Gardinerella vaginalis



Neisseria meningitides




Bacteria causing Diseases in Plants

Name of Bacteria


Site of Infection

Pseudomonas solanaecearum

Potato wilt

Potato, tomato

Erwinia atroseptica

Black rot disease of potato

Stem and tuber of potato

Xanthomonas citri

Citrus canker

premature leaf and fruit drop

Agrobacterium radiobacter

Crown gall

roots, twigs, and branches

Erwinia amylovora

Fire blight of apple

Vascular tissue of apple

Xanthomonas oryzae

Bacterial blight of apple


Pseudomonas rubrilineans

Red stripe of sugarcane


Erwinia cartovora

Soft rot of carrot

decay of the taproot

Corynebacterium tritci

Tundu (bacterial rot) of wheat

twisting of the stem etc.

Corynebacterium campestris

Black rot of cabbage

Young branches, leaves, fruits

Streptomyces scabies

Potato scab

Potato tuber

Pseudomonas tobaci

Wild fire of tobacco


Bacterium stewartii

Wilt disease of corn

Vascular tissue of corn

Pseudomonas maculicola

Cauliflower spot disease



Bacteria causing Diseases in Animals

Name of Bacteria


Site of Infection

Bacillus antracis

Anthrax disease


Yersinia pestis



Coxiella burnetti

Q fever

Birds and rats

Leptospira interrogans



Actinomycis bovis

Ray fungus dis­ease



So, this was all about the Economic Importance of Bacteria – Useful and Harmful Effects and Role of Bacteria in various fields. If you want to read more notes on Biology than – Click Here.

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