Context: The "Proteobacteria" are a major phylum of Gram-negative bacteria. The name of the phylum has never been validly published as no type genus has been proposed, thus it must be styled in quotation marks as the name has no standing in nomenclature. They include a wide variety of pathogens, such as "Escherichia", "Salmonella", "Vibrio", "Helicobacter", "Yersinia", and many other notable genera.
Others are free-living (nonparasitic), and include many of the bacteria responsible for nitrogen fixation., Plants are mainly multicellular, predominantly photosynthetic eukaryotes of the kingdom Plantae., Cyanobacteria , also known as Cyanophyta, is a phylum of bacteria that obtain their energy through photosynthesis. The name "cyanobacteria" comes from the color of the bacteria (= blue). Sometimes, they are called blue-green algae, and incorrectly so, because cyanobacteria are prokaryotes and the term "algae" is reserved for eukaryotes., Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that can later be released to fuel the organisms' activities (energy transformation). This chemical energy is stored in carbohydrate molecules, such as sugars, which are synthesized from carbon dioxide and water  hence the name "photosynthesis", from the Greek , "phs", "light", and , "synthesis", "putting together". In most cases, oxygen is also released as a waste product. Most plants, most algae, and cyanobacteria perform photosynthesis; such organisms are called photoautotrophs. Photosynthesis is largely responsible for producing and maintaining the oxygen content of the Earth's atmosphere, and supplies all of the organic compounds and most of the energy necessary for life on Earth., Fermentation is a metabolic process that converts sugar to acids, gases, or alcohol. It occurs in yeast and bacteria, and also in oxygen-starved muscle cells, as in the case of lactic acid fermentation. Fermentation is also used more broadly to refer to the bulk growth of microorganisms on a growth medium, often with the goal of producing a specific chemical product. French microbiologist Louis Pasteur is often remembered for his insights into fermentation and its microbial causes. The science of fermentation is known as zymology., Energy transformation or energy conversion is the process of changing one form of energy to another form of energy. In physics, the term energy describes the capacity to produce certain changes within any system, without regard to limitations in transformation imposed. Changes in total energy of systems can only be accomplished by adding or removing energy from them, as energy is a quantity which is conserved (unchanging), as stated by the first law of thermodynamics. Mass-energy equivalence, which rose up from special relativity, states that changes in the energy of systems will also coincide with changes (often small in practice) in the system's mass, and the mass of a system is a measure of its energy content. The process of something happening (forming)., The Rhodospirillaceae are a family of Proteobacteria. The majority are purple nonsulfur bacteria, producing energy through photosynthesis; originally all purple nonsulfur bacteria were included here., In chemistry, an alcohol is any organic compound in which the hydroxyl functional group (OH) is bound to a saturated carbon atom. The term alcohol originally referred to the primary alcohol ethanol (ethyl alcohol), the predominant alcohol in alcoholic beverages., Oxygen is a chemical element with symbol O and atomic number 8. It is a member of the chalcogen group on the periodic table and is a highly reactive nonmetal and oxidizing agent that readily forms oxides with most elements as well as other compounds. By mass, oxygen is the third-most abundant element in the universe, after hydrogen and helium. At standard temperature and pressure, two atoms of the element bind to form dioxygen, a colorless and odorless diatomic gas with the formula . This is an important part of the atmosphere and diatomic oxygen gas constitutes 20.8% of the Earth's atmosphere. Additionally, as oxides the element makes up almost half of the Earth's crust., Purple bacteria or purple photosynthetic bacteria are proteobacteria that are phototrophic, that is, capable of producing their own food via photosynthesis. They are pigmented with bacteriochlorophyll "a" or "b", together with various carotenoids, which give them colours ranging between purple, red, brown, and orange. They may be divided into two groups  purple sulfur bacteria (Chromatiales, in part) and purple non-sulfur bacteria (Rhodospirillaceae)., The heliobacteria are phototrophic : they convert light energy into chemical energy by photosynthesis and they use a Type I reaction centerHeinickel and Golbeck 2007 . The primary pigment involved is bacteriochlorophyll g , which is unique to the group and has a unique absorption spectrum ; this gives the heliobacteria their own environmental niche . Phototrophy takes place at the cell membrane , which does not form folds or compartments as it does in purple bacteria . Even though heliobacteria are phototrophic , they can grow without light by fermentation of pyruvate . RNA trees place the heliobacteria among the Firmicutes but they do not stain gram - positively . They have no outer membrane and like certain other firmicutes ( clostridia ) they form heat resistant endospores , which contain high levels of calcium and dipicolinic acid . Heliobacteria are the only firmicutes known to conduct photosynthesis . Heliobacteria are photoheterotrophic , requiring organic carbon sources , and they are exclusively anaerobic . Chlorophyll g is inactivated by the presence of oxygen , making them obligate anaerobes ( they can not survive in aerobic conditions ) . So far heliobacteria have only been found in soils , and are apparently widespread in the waterlogged soils of paddy fields . They are avid nitrogen fixers and are therefore probably important in the fertility of paddy fields ., Yeasts are eukaryotic, single-celled microorganisms classified as members of the fungus kingdom. The yeast lineage originated hundreds of millions of years ago, and 1,500 species are currently identified. They are estimated to constitute 1% of all described fungal species. Yeasts are unicellular organisms which evolved from multicellular ancestors, with some species having the ability to develop multicellular characteristics by forming strings of connected budding cells known as pseudohyphae or false hyphae. Yeast sizes vary greatly, depending on species and environment, typically measuring 34 µm in diameter, although some yeasts can grow to 40 µm in size. Most yeasts reproduce asexually by mitosis, and many do so by the asymmetric division process known as budding., Sulfur or sulphur (see spelling and etymology) is a chemical element with symbol S and atomic number 16. It is abundant, multivalent, and nonmetalic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with chemical formula S. Elemental sulfur is a bright yellow crystalline solid at room temperature. Chemically, sulfur reacts with all elements except for gold, platinum, iridium, tellurium, and the noble gases., The purple sulfur bacteria are a group of Proteobacteria capable of photosynthesis, collectively referred to as purple bacteria. They are anaerobic or microaerophilic, and are often found in hot springs or stagnant water. Unlike plants, algae, and cyanobacteria, they do not use water as their reducing agent, so do not produce oxygen. Instead, they use hydrogen sulfide, which is oxidized to produce granules of elemental sulfur. This, in turn, may be oxidized to form sulfuric acid., Algae (singular "alga" ) is an informal term for a large, diverse group of photosynthetic organisms which are not necessarily closely related, and is thus polyphyletic. Included organisms range from unicellular genera, such as "Chlorella" and the diatoms, to multicellular forms, such as the giant kelp, a large brown alga which may grow up to 50 m in length. Most are aquatic and autotrophic and lack many of the distinct cell and tissue types, such as stomata, xylem, and phloem, which are found in land plants. The largest and most complex marine algae are called seaweeds, while the most complex freshwater forms are the Charophyta, a division of green algae which includes, for example, "Spirogyra" and the stoneworts., Phototrophs ("Gr": ,  = light,  = nourishment) are the organisms that carry out photon capture to acquire energy. They use the energy from light to carry out various cellular metabolic processes. It is a common misconception that phototrophs are obligatorily photosynthetic. Many, but not all, phototrophs often photosynthesize: they anabolically convert carbon dioxide into organic material to be utilized structurally, functionally, or as a source for later catabolic processes (e.g. in the form of starches, sugars and fats). All phototrophs either use electron transport chains or direct proton pumping to establish an electro-chemical gradient which is utilized by ATP synthase, to provide the molecular energy currency for the cell. Phototrophs can be either autotrophs or heterotrophs., Bacteria (common noun bacteria, singular bacterium) constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a number of shapes, ranging from spheres to rods and spirals. Bacteria were among the first life forms to appear on Earth, and are present in most of its habitats. Bacteria inhabit soil, water, acidic hot springs, radioactive waste, and the deep portions of Earth's crust. Bacteria also live in symbiotic and parasitic relationships with plants and animals., Zymology, also known as zymurgy (from the Greek: +, "the workings of fermentation") is an applied science which studies the biochemical process of fermentation and its practical uses. Common topics include the selection of fermenting yeast and bacteria species and their use in brewing, wine making, fermenting milk, and the making of other fermented foods., Lactic acid is an organic compound with the formula CHCH(OH)COH. In its solid state, it is white and water-soluble. In its liquid state, it is clear. It is produced both naturally and synthetically. With a hydroxyl group adjacent to the carboxyl group, lactic acid is classified as an alpha-hydroxy acid (AHA). In the form of its conjugate base called lactate, it plays a role in several biochemical processes., Subject: heliobacteria, Relation: taxon_rank, Options: (A) division (B) domain (C) family (D) form (E) group (F) kingdom (G) phylum (H) species
Output: family