'Photoheterotrophs' (or 'photoorganotrophs') are
heterotrophic organisms which use light for energy, but cannot use carbon dioxide as their sole carbon source. Consequently, they use organic compounds from the environment to satisfy their carbon requirements. Examples are
purple non-sulfur bacteria,
green non-sulfur bacteria and
heliobacteria.
Sources
University of Wisconsin, Madison Microbiology Online Textbook
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