more oxygen was produced. But because of the bacteria's behavior in the focused light, it was concluded that the bacteria's photosynthetic byproduct could not be oxygen. In a 2018 article, it has been suggested that purple bacteria can be used as a biorefinery. Evolution Researchers have theorized that some purple bacteria are related to the mitochondria, symbiotic bacteria in plant and animal cells today that act as organelles. Comparisons of their protein structure suggests that there is a common ancestor. References Pseudomonadota Phototrophic bacteria