Photosynthesis: Anoxygenic Phototrophs and Carbon Fixation

This lecture covers the process of photosynthesis in anoxygenic phototrophs, such as purple sulfur bacteria and green sulfur bacteria, explaining the role of carotenoids and the different energy sources, carbon sources, and electron donors involved. It also delves into the mechanisms of carbon fixation, including the Calvin-Benson-Bassham cycle and the reductive citric acid cycle, highlighting the key enzymes and intermediate compounds. The lecture further explores the pathways for CO2 fixation, such as the Reductive Acetyl-CoA pathway, and the organisms that utilize them, like autotrophic acetogens and sulfate-reducing bacteria. Additionally, it discusses the role of methanogens in producing methane from CO2 and H2. The importance of these processes in the context of environmental microbiology and biogeochemistry is emphasized.