Purple bacteria are a group of photosynthetic microorganisms that belong to the phylum Proteobacteria. They are known for their distinctive purple pigments, which help them capture light energy for photosynthesis. These bacteria can be found in various environments, including freshwater, saltwater, and even in some soil. These bacteria primarily use anoxygenic photosynthesis, meaning they do not produce oxygen as a byproduct. Instead, they utilize light energy to convert carbon compounds into energy-rich molecules. Purple bacteria play a crucial role in their ecosystems by contributing to nutrient cycling and serving as a food source for other organisms.