Autotrophic bacteria don't break down anything in their environment for energy. They actually make their own food, which is why they're called "autotrophs" (meaning "self-feeding").

Here's how they get their energy:

* Photoautotrophs: These bacteria use light energy to convert carbon dioxide and water into sugars (like glucose) through photosynthesis, just like plants do.

* Chemoautotrophs: These bacteria use chemical energy from inorganic compounds like hydrogen sulfide, ammonia, or iron to generate energy. They do this through chemosynthesis.

So, instead of breaking down things in their environment for energy, they use light or chemicals to create their own food source.