Photosynthetic and quasi-photosynthetic bacteria

Abstract

The term photosynthesi was coined in 1893 to represent the light-dependent conversion of CO2 and water to organic compounds and molecular oxygen. Despite the discovery in 1907 that bacteriochlorophyll-containing purple bacteria do not produce molecular oxygen and can grow on organic carbon sources using light as the energy source, photosynthesis is still frequently defined as an oxygenic autotrophic process. The meanings of the terms photosynthesis and phototrophy have become increasingly obfuscated, especially by the recent isolation of a number of aerobic bacterial species which produce bacteriochlophyll but appear unable to use light as an energy source for appreciable biosynthesis. This paper focuses on the importance of formulating a more precise definition of photosynthesis, and thereby forcesrecognition of the existence of a class of 'quasi-photosynthetic' bacterial species whose bioenergetic patterns require further analysis.