Purple bacteria or purple photosynthetic bacteria are proteobacteria that are phototrophic, i.e. capable of producing energy through photosynthesis. They are pigmented with bacteriochlorophyll a or b, together with various carotenoids. These give them colours ranging between purple, red, brown, and orange. Photosynthesis takes place at reaction centers on the cell membrane, which is folded into the cell to form sacs, tubes, or sheets, increasing the available surface area. Orders Alpha Proteobacteria    Caulobacterales - e. ... Phototrophs or photoautotrophs are photosynthetic algae, fungi, bacteria and cyanobacteria which build up carbon dioxide and water into organic cell materials using energy from sunlight. ... The leaf is the primary site of photosynthesis in plants. ... Bacteriochlorophylls are photosynthetic pigments that occur in various bacteria. ... Carotenoids are organic pigments that are naturally occurring in plants and some other photosynthetic organisms like algae, some types of fungus and some bacteria. ... Illustration of a lipid bilayer A cell membrane, plasma membrane or plasmalemma is a selectively permeable lipid bilayer coated by proteins which comprises the outer layer of a cell. ...

Like most other photosynthetic bacteria, purple bacteria do not produce oxygen, because the reducing agent involved in photosynthesis is not water. In some, called purple sulfur bacteria, it is either sulfide or elemental sulfur. The others, called purple non-sulfur bacteria (aka PNSB), typically use hydrogen although some may use other compounds in small amounts. At one point these were considered families, but RNA trees show the purple bacteria make up a variety of separate groups, each closer relatives of non-photosynthetic proteobacteria than one another. General Name, Symbol, Number oxygen, O, 8 Chemical series Nonmetals, chalcogens Group, Period, Block 16, 2, p Appearance colorless (gas) very pale blue (liquid) Atomic mass 15. ... A reducing agent is the element or a compound in a redox (reduction-oxidation) reaction (see electrochemistry) that reduces another species. ... Families Chromatiaceae Ectothiorhodospiraceae Halothiobacillaceae The purple sulfur bacteria are a group of Proteobacteria capable of photosynthesis, collectively referred to as purple bacteria. ... Formally, sulfide is the dianion, S2−, which exists in strongly alkaline aqueous solutions formed from H2S or alkali metal salts such as Li2S, Na2S, and K2S. Sulfide is exceptionally basic and, with a pKa > 14, it does not exist in appreciable concentrations even in highly alkaline water. ... General Name, Symbol, Number sulfur, S, 16 Chemical series nonmetals Group, Period, Block 16, 3, p Appearance lemon yellow Atomic mass 32. ... General Name, Symbol, Number hydrogen, H, 1 Chemical series nonmetals Group, Period, Block 1, 1, s Appearance colorless Atomic mass 1. ...

Purple non-sulfur bacteria are found among the alpha and beta subgroups, including:

Purple sulfur bacteria are included among the gamma subgroup, and make up the order Chromatiales. The similarity between the photosynthetic machinery in these different lines indicates it had a common origin, either from some common ancestor or passed by lateral transfer. Families Rhodospirillaceae Acetobacteraceae The Rhodospirillales are an order of proteobacteria, with two families. ... Genera Rhodospirillum Azospirillum Magnetospirillum Phaeospirillum Rhodocista Rhodospira Rhodothalassium Rhodovibrio Roseospira Skermanella The Rhodospirillaceae are a family of Proteobacteria. ... Genera Acetobacter Acidiphilium Acidocella Acidomonas Craurococcus Gluconacetobacter Gluconobacter Paracraurococcus Rhodopila Roseococcus Stella Zavarzinia Acetic acid bacteria are bacteria that derive their energy from the oxidation of ethanol to acetic acid during respiration. ... Families Aurantimonadaceae Bartonellaceae Beijerinckiaceae Bradyrhizobiaceae Brucellaceae Hyphomicrobiaceae Methylobacteriaceae Methylocystaceae Phyllobacteriaceae Rhizobiaceae Rhodobiaceae The Rhizobiales are an order of alpha proteobacteria. ... Genera Afipia Agromonas Blastobacter Bosea Bradyrhizobium Nitrobacter Oligotropha Photorhizobium Rhodoblastus Rhodopseudomonas The Bradyrhizobiaceae are a family of bacteria, with ten genera. ... Genera Ancalomicrobium Ancylobacter Angulomicrobium Aquabacter Azorhizobium Blastochloris Devosia Dichotomicrobium Filomicrobium Gemmiger Hyphomicrobium Labrys Methylorhabdus Pedomicrobium Prosthecomicrobium Rhodomicrobium Rhodoplanes Seliberia Starkeya Xanthobacter The Hyphomicrobiaceae are a family of bacteria. ... Species Rhodobium is a genus of purple non-sulfur bacteria that reproduces by budding. ... Genera Ahrensia Albidovulum Amaricoccus Antarctobacter Catellibacterium Citricella Hyphomonas group Jannaschia Ketogulonicigenium Leisingera Loktanella Marinosulfonomonas Methylarcula Oceanibulbus Oceanicaulis Oceanicola Octadecabacter Pannonibacter Paracoccus Phaeobacter Pseudorhodobacter Pseudovibrio Rhodobaca Rhodobacter Rhodothalassium Rhodovulum Roseibacterium Roseibium Roseinatronobacter Roseisalinus Roseivivax Roseobacter Roseovarius Rubrimonas Ruegeria Sagittula Salipiger Silicibacter Staleya Stappia Sulfitobacter Tetracoccus Thioclava The Rhodobacteraceae are a family... The Rhodocyclaceae are a family of gram-negative bacteria. ... Genera Acidovorax Aquabacterium Brachymonas Comamonas Delftia Hydrogenophaga Ideonella Leptothrix Polaromonas Rhodoferax Roseateles Sphaerotilus Tepidimonas Thiomonas Variovorax The Comamonadaceae are a family of Proteobacteria. ... Families Chromatiaceae Ectothiorhodospiraceae Halothiobacillaceae The purple sulfur bacteria are a group of Proteobacteria capable of photosynthesis, collectively referred to as purple bacteria. ...