Heterotrophic bacteria derive energy from organic compounds. They are widely distributed and most abundant forms. They may be aerobic or anaerobic. They are omnipresent and found in the food, soil, water. They help in recycling of natural substances.
They are mostly liable for the decomposition of organic matter. They also live as a parasite and cause various diseases in plants, animals and humans. They are also present as a symbiont in organisms, e.g. Rhizobium in the root nodules of legumes, etc.
Bacteria are used for creating curd, antibiotics, nitrogen-fixation, etc. Organic matters such as cellulose, chitin, keratin and lignin can be decomposed by Heterotrophic bacteria.
What are the Different Types of Heterotrophic Bacteria?
According to their habitat, food source and association with other organisms, heterotrophic bacteria can be divided into three main categories:
Parasitic – They derive their food from living organisms
Saprophytic – They prey on dead and decaying organic matter
Symbiotic – They live in symbiotic in close contact with other organisms.
Heterotrophic Bacteria Types and Examples
Parasitic bacteria could also be a parasite on animals or plants. Not all parasitic bacteria are pathogenic, e.g. microbial flora of the human body, present in skin, digestive tract, mucous membranes and other organs, coexist without harming.
Many diseases can also be caused by Pathogenic Heterotrophic Bacteria. They have different modes of infection and transmission. Some examples are:
Citrus canker – Xanthomonas axonopodis
Crown gall – Agrobacterium tumefaciens
Blight of beans – Xanthomonas campestris
Wildfire of Tobacco – Pseudomonas syringae
Granville wilt – Pseudomonas solanacearum
Cholera – Vibrio cholerae
Typhoid – Salmonella typhi
Tetanus – Clostridium tetani
Whooping cough – Bordetella pertussis
Lyme disease – Borrelia
Diphtheria – Corynebacterium diphtheriae
Diarrhoea – Escherichia coli
Tuberculosis – Mycobacterium tuberculosis
Gonorrhoea – Neisseria gonorrhoeae
Rhizobium present in root nodules of legumes may be a common example of symbiotic bacteria. Bacteria present in the gut of humans and ruminants help in digesting food. They also help in producing vitamins.
They are the main decomposers of the food chain with fungi. Complex organic matter is being broken down to simple compounds by Saprophytic Bacteria and then assimilated. They help in nutrient recycling.
Characteristics of Bacteria
Bacteria mainly comprises a simple cellular structure, including:
These microorganisms are found everywhere, all around us and are found in communities of millions. The shape of bacteria varies with the types and the length of complete bacteria measures only a few micrometres.
Other Structural Features of these Prokaryotic Microorganisms are:
It lacks a membrane-bound nucleus.
It consists of a circular-shaped, single chromosome of DNA that can be found within the cytoplasm.
Every bacterial cell possesses its own plasmids, which are involved in replication, food digestion, etc.
These plasmids are small, circular, double-stranded DNA Structures, which are naturally found altogether in bacterial cells.
Bacteria use both sexual and asexual methods for reproduction. Most bacteria rely on binary fission.
There are several different types of bacteria and therefore the classification of Bacteria are mainly supported their
Mode of Respiration – Aerobic or Anaerobic.
Nutritional Patterns: Autotrophic or heterotrophic.
Reproduction: Binary fission, conjugation, transduction and transformation.
Shapes: Bacillus, Coccus, spirillum or spirochete and Vibrio.
Cell wall composition: Gram-positive and Gram-negative.
Interesting Facts about Bacteria
Bacteria play a primary role in regulating biogeochemical systems.
These bacteria also protect our body from defending the invading pathogens.
The smell of rain is also caused by a certain group of gram-positive bacteria present in the soil.
Compared to the other human body parts, mouth and belly buttons have more than a thousand to millions of new species of bacteria.
Bacteria act as cleaning and disinfectant agents.
These bacteria are both beneficial and harmful for humans, animals and also for plants.
Bacteria can be found in both outside the body and deep inside in our gut which helps indigestion.
Sphere, Rod, Spiral and Spherical are the different shapes in which Bacteria can be found.
There are many bacteria present in our gut which helps in digestion and protects our body from defending the invading pathogens, also known as Good bacteria.
Bacteria form a crucial part of the ecosystem, which takes part in activities like production of gases like oxygen, carbon dioxide and nitrogen and minerals like nitrogen, sulphur, etc.
Bacteria are used in various food and beverage industries, the pharmaceutical industry, in the production of biofuel, biopesticides and so on.
10 times more bacterial cells can be found in bacterial cells than human cells. These bacteria may either be good bacteria like various bacterial infections and other fatal diseases.