types of nutrition adopted by microorganisms

7 Basic Nutrition Adopted By Microorganisms – Learn Easy

In this tutorial we learn about the types of nutrition adopted by microorganisms such as heterotrophs, mixotrophs, auxotrophs, protoautotroph, pathogens and symbionts

Heterotrophs

          Heterotrophs are a Nutrition adopted by microorganisms that cannot synthesise their food using inorganic sources like carbon dioxide and their dependence upon complex organic substances as a source of carbon are called Heterotrophs. 95% of all living organisms are heterotrophs including animals, fungi and most bacteria, called consumers.

Heterotrophs are those that break down complex organic compounds such as carbohydrates, fats and protein produced by autotrophs into simpler compounds, carbohydrates to glucose, fats to fatty acids and glycerol and proteins into amino acids.

Nutrition adopted by microorganisms that specifically feed on the dead and decayed organic matter is called Saprophytes and release energy by oxidising carbon and hydrogen atoms present in these organic compounds to carbon dioxide and water respectively.

types of nutrition adopted by microorganisms
Heterotrophs

Organotrophs

An organotroph is nutrition adopted by microorganisms that use organic compounds as electron donors. Organotrophs are heterotrophs using organic compounds as sources of electrons and carbon and use the chemical bonds in the organic compounds as an energy source. These organic compounds include carbohydrates, fatty acids, alcohols.

Example: Rhodospirillum uses fatty acids to derive energy, purple non-Sulphur bacteria organotrophic bacteria.

types of nutrition adopted by microorganisms
Rhodospirillum rubrum

Mixotrophs

A Mixotroph is a nutrition adopted by microorganisms that can utilise a mixture of various sources of energy and carbon, as a replacement for having a single trophic mode of autotrophy at one end to heterotrophy at the other.

Mixotrophs can be either eukaryotic or prokaryotic and can take advantage of different environmental conditions. Mixotrophs can either be obligate or facultative, and the combination can be photo and chemotrophy, litho and organotrophy or auto and heterotrophy.

Example:  Beggiota sp

types of nutrition adopted by microorganisms
 Beggiota Sp

Auxotroph

An auxotroph (Auxo means to increase nourishment) of an organism is defined as the inability of the organism to synthesise a particular organic compound required for its growth. For example, E.coli cannot grow until histidine, supplied in the media.

Auxotrophy results from a cell’s genetically determined inability to produce a reasonable amount of functional enzymes catalyse the synthesis of essential growth factors. Replica plating techniques is an essential method for the isolation of auxotrophic mutants.

Protoautotroph

          Protoautotroph is one type of nutrition adopted by microorganisms that can synthesise all the compounds required for its growth, that parent organism could and requires minimal culture media that lacks even certain growth factors. E.coli can thrive and synthesise all its cell components in a solution containing several minerals and glucose as a source of energy and carbon. Protoautotrophs are precisely opposite to auxotrophs.

Pathogens

          Pathogens (Pathos means Suffering) or  Parasites are nutrition adopted by microorganisms that cause suffering or disease in other living organisms and are heterotrophs that depend on other organisms for their nutrients and multiplication and benefit themselves by causing harm to the host cell and the organism that harbours the parasites called as a host.

Examples: Mycobacterium tuberculosis causing disease in humans and Xanthomonas oryzae, causing bacterial blight in paddy plants.

types of nutrition adopted by microorganisms
Mycobacterium tuberculosis

Symbionts

Symbionts mean together, organisms that live in association with other organisms for food and shelter. This symbiotic relationship where both participating symbionts benefit from each other is now referred to as mutualism.

Symbionts in mutualism are often interdependent—the interaction between Rhizobia species and the plant legumes. The symbiont Rhizobia fix atmospheric nitrogen to a readily available nitrogen source for use by the legume.

In return, legume provides Rhizobia with specific metabolites (Malate and Succinate) through the process of photosynthesis.

Example: Rhizobium and Leguminous plants.

types of nutrition adopted by microorganisms
Nodules of Rhizobium Legumonosarum

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Autotrophs are Manufacturers of Food

Autotrophs are Manufacturers of Food

Autotrophs are Manufacturers of Food

An Autotroph – “ Self-Feeding”, from the Greek autos “Self” and trope “Nourishing”, is an organism that fabricates complex organic compounds such as carbohydrates, fats, and proteins from simple substances present in its surroundings. In short, they are the producer organisms that can make their food by photosynthesis or chemosynthesis and occupy the first trophic level.

Autotrophs are Manufacturers of Food
Autotrophs – Manufacturers of Food

Photoautotrophs – Manufacturers of Food by Photosynthesis

Photoautotrophs are autotrophic organisms that carry out photosynthesis using energy from sunlight, carbon dioxide as terminal electron acceptor and water, converted into organic materials used in cellular functions such as biosynthesis and respiration. There are fabricators in a food chain like plants on land and algae on the water (Eukaryotes). In the case of Prokaryotes, Purple Sulphur bacteria and Cyanobacteria are photoautotrophic prokaryotes.

Chemotrophs – Manufacturers of Food by chemosynthesis

          Chemotrophs are organisms that make their food by chemosynthesis. It is a process that synthesises organic compounds from carbon dioxide using chemical energy by utilising inorganic compounds like hydrogen sulphide, sulphur, ammonium and ferrous iron as reducing agents found in hostile environments like deep-sea vents, where light cannot easily penetrate.

Examples: Methanogens, Halophiles, Nitrifiers, Thermoacidophiles

Lithotrophs

          Lithotrophs are consumers of rocks. They are autotrophs that use an inorganic substrate of mineral origin as reducing agents or electron donors for the biosynthesis of organic compounds. Hence they are also called Chemolithotrophs. They produce a particular toxin that dissolves the minerals present in the rocks.

Examples: Purple sulphur bacteria, Nitrifying bacteria, and Hydrogen oxidisers.

Also, check out our post about Saprophytes.

Saprophytes as Biocontrol Agents

Saprophytes as Biocontrol Agents

In this tutorial, you’ll learn about Saprophytes as Biocontrol Agents

Saprophytes

Saprophytes are organisms that develop on the dead and rotting natural issue and do not make any infections plants or creatures. Fungi are an ideal case of saprophytes. The expansion of saprophytes is a deep-rooted act of controlling plant pathogens. This procedure is a proficient biological control, rehearsed since days of yore. Expansion of these saprophytes to the yields likewise upgrades the harvest generation by giving numerous supplements and by counteracting plant pathogens. In contrast to synthetic compounds, used to control pathogens, these saprophytes have pulled in the consideration due to the accompanying elements:

•        As they do not bring on any ailment

•        Also, increment the creation of the yield

•        Prevents numerous maladies which cause devastation

•        Increases the capacity of the plants to oppose the sicknesses

•        Less natural dangers

Saprophytes as Biocontrol Agents

Saprophytes as Biocontrol Agents Methods

  • Antagonism
    • Competition
    • Use of predative microbes
    • Parasitic fungi on plant pathogens
      • Mycoparasitism
      • Mycophagy
      • Nematophagy
      • Mycoviruses
  • Siderophores

Examples of siderophores produced by various bacteria and fungi:

Ferrichrome, a hydroxamate siderophore

Desferrioxamine B, a hydroxamate siderophore

Enterobactin, a catecholate siderophore

Azotobactin, a mixed-ligand siderophore

Pyoverdine, a mixed-ligand siderophore

Yersiniabactin, a mixed-ligand siderophore

  • Seed Inoculation
  • Green Manuring
  • Crop Rotation
  • Irrigation
  • Alteration of Soil pH
  • Organic amendments
  • Organic manure
  • Use of mycorrhiza
  • Allelopathy