- Organic compounds: Bacteria can use organic compounds as a source of carbon and energy. Such organic compounds can include sugars, carbohydrates, proteins, and fats.
- Inorganic compounds: Some bacteria can also use inorganic compounds as a source of carbon and energy. For instance, some bacteria may utilize carbon dioxide as a carbon source and water as an energy source.
- Light: Photosynthetic bacteria can use light energy to convert carbon dioxide into organic compounds, a process known as photosynthesis.
- Heat: some bacteria can derive energy from heat, known as thermophilic bacteria. They thrive in hot environments, such as volcanic springs or deep sea hydrothermal vents.
