Important Differences between Photosynthetic and Chemosynthetic Bacteria

Both photosynthesis and chemosynthesis are processes wherein entities produce food. While the process of photosynthesis is fuelled by sunlight, chemosynthesis is powered by chemical energy.

The entire ecosystem is based on the capability of some of the entities in converting inorganic compounds to food which other entities can consume. Mostly, primary food production takes place by photosynthesis. In some other surroundings, the primary production takes place through chemosynthesis that is fuelled by chemical energy.

Photosynthetic and chemosynthetic bacteria vary from each other in the fact that photosynthetic bacteria gain their energy from sunlight for the production of carbohydrates. On the other hand, chemosynthetic bacteria get their energy from the oxidation of inorganic compounds for the production of carbohydrates.

Photosynthetic Bacteria

  • These are essentially prokaryotes having the capability of converting light energy into chemical energy via photosynthesis
  • Since it makes its own energy with the use of inorganic substances, these are also referred to as photoautotrophs. Hence, they are not completely dependent on other entities for energy
  • There is a wide range of photosynthetic bacteria spread across aquatic and terrestrial habitats. Here, these entities also serve as primary producers

Chemosynthetic Bacteria

  • These are the bacteria synthesizing organic compounds with the energy obtained from the oxidation of the organic or the inorganic substances without the need for light
  • These bacteria include a group of autotrophic bacteria using chemical energy for the production of their own food
  • They require a carbon source too as a source of energy to synthesize their own food
  • Mostly, these bacteria are aerobic while some are anaerobic too
  • Since it can manufacture its own food, it uses chemical energy. These entities can survive in different environments either in association with entities (symbiosis) or as free-living entities

Key Difference between Photosynthetic and Chemosynthetic Bacteria

The table below depicts the difference between photosynthetic and chemosynthetic bacteria.

Photosynthetic Bacteria

Chemosynthetic Bacteria

What are they?

These entities perform photosynthesis to synthesize their own food

These entities perform chemosynthesis to synthesize their own food

Is sunlight required?



Source of energy

Solar energy

Inorganic substances

Can they fix nitrogen?




Cyanobacteria, Proteobacteria

Venenivibrio stagnispumantis, T. neapolitanus, Beggiatoa, ferrooxidans

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