Photosynthesis originated in the domain Bacteria billions of years ago; however, the identity of the last common ancestor to all phototrophic bacteria remains undetermined and speculative. Here I present the evolution of BchF or 3-vinyl-bacteriochlorophyll hydratase, an enzyme exclusively found in bacteria capable of synthetizing bacteriochlorophyll a. I show that BchF exists in two forms originating from an early divergence, one found in the phylum Chlorobi, including its paralogue BchV, and a second form that was ancestral to the enzyme found in the remaining anoxygenic phototrophic bacteria. The phylogeny of BchF is consistent with bacteriochlorophyll a evolving in an ancestral phototrophic bacterium that lived before the radiation event that gave rise to the phylum Chloroflexi, Chlorobi, Acidobacteria, Proteobacteria, and Gemmatimonadetes, but only after the divergence of Type I and Type II reaction centers. Consequently, it is suggested that the lack of phototrophy in many groups of extant bacteria is a derived trait.
Lichens are mutualistic associations consisting of a primary fungal host, and one to few primary phototrophic symbiont(s), usually a green alga and/or a cyanobacterium. They form complex thallus structures, which provide unique and stable habitats for many other microorganisms. Frequently isolated from lichens are the so-called black fungi, or black yeasts, which are mainly characterized by melanized cell walls and extremophilic lifestyles.
Purple phototrophic bacteria produce two kinds of light-harvesting complexes that function to capture and transmit solar energy: the core antenna (LH1) and the peripheral antenna (LH2). The apoproteins of these antennas, encoded respectively by the genes pufBA and pucBA within and outside the photosynthetic gene cluster, respectively, exhibit conserved amino acid sequences and structural topologies suggesting they were derived from a shared ancestor. Here we present the structures of two photosynthetic complexes from Roseospirillum (Rss.
This research looked at how three different light intensities (1600, 4300, and 7200 lx) affect the biomass development, treatment of fuel synthesis wastewater and the recovery of valuable bioproducts between biofilm and suspended growth in a purple-bacteria enriched photobioreactor. Each condition was run in duplicate using an agricultural shade cloth as the biofilm support media in a continuously mixed batch reactor. The results showed that the highest chemical oxygen demand (COD) removal rate (56.
is a hot spring purple nonsulfur phototrophic bacterium that contains bacteriochlorophyll (BChl) . Here, we present a 2.21 Å cryo-EM structure of the thermostable light-harvesting 1-reaction center (LH1-RC) complex from .
Excitation energy transfer between the photochemically active protein complexes is key for photosynthetic processes. Phototrophic organisms like cyanobacteria experience subtle changes in irradiance under natural conditions. Such changes need adjustments to the excitation energy transfer between the photosystems for sustainable growth.
