Phototrophic purple and green bacteria can be classified into four main groups based on their ability to use sulfur compounds for oxidation: purple sulfur bacteria, purple non-sulfur bacteria, green sulfur bacteria, and green non-sulfur bacteria.

Classification of Purple and Green Bacteria

Purple and green bacteria are phototrophic bacteria that utilize bacteriochlorophyll to perform photosynthesis. They are also responsible for the pigment of these bacteria. They also have carotenoids to absorb different wavelengths of light and changes their colors. 

University of Wisconsin - Madison

Phototrophic bacteria use sunlight as their energy source. Phototrophic bacteria consist of many groups: 
- Purple and Green bacteria
- Cyanobacteria

Phototrophic Bacteria

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Microbiology covers the scope and sequence requirements for a single-semester microbiology course for non-majors. The book presents the core concepts of microbiology with a focus on applications for careers in allied health. The pedagogical features of the text make the material interesting and accessible while maintaining the career-application focus and scientific rigor inherent in the subject matter. Microbiology’s art program enhances students’ understanding of concepts through clear and effective illustrations, diagrams, and photographs.

Microbiology is produced through a collaborative publishing agreement between OpenStax and the American Society for Microbiology Press. The book aligns with the curriculum guidelines of the American Society for Microbiology.

OpenStax Microbiology Textbook

Cyanobacteria are a phylum of bacteria that contain chlorophyll and perform photosynthesis. They have been postulated to play a role in the switch to the primarily oxygen-rich atmosphere we have today which is a switch that happened millions of years ago.

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