A Photobioreactor is a special type of container that helps us grow algae. Algae are a type of plant and they can be used to make food, fuel, and medicine. The photobioreactor has lights inside it, which helps the algae grow. The reactor also has pumps that pump water in and out. This helps the algae get the nutrients it needs to grow properly. The photobioreactor is like a special green house for algae!