Microbial Nutrition

Organisms exhibit metabolic diversity based on how they acquire energy and carbon sources.

Phototrophs use light for energy, while chemotrophs obtain energy by oxidizing chemical compounds.

Autotrophs use carbon dioxide while heterotrophs rely on organic molecules for their carbon source.

These classifications combine to form groups like photoautotrophs, photoheterotrophs, chemoautotrophs, and chemoheterotrophs.

Photoautotrophs, such as cyanobacteria and algae, use light as an energy source and carbon dioxide as a carbon source, releasing oxygen during photosynthesis.

Photoheterotrophs, such as purple nonsulfur bacteria, rely on light for energy and require organic carbon sources.

Chemoautotrophs oxidize inorganic compounds, such as hydrogen sulfide, nitrogen, sulfur, and ammonia, for energy and use carbon dioxide as their carbon source, playing a crucial role in nutrient cycling.

Chemoheterotrophs obtain both energy and carbon from organic molecules. They are crucial for decomposing organic matter and recycling nutrients. Nearly all human pathogenic microorganisms belong to this group.