Autotrophic Bacteria

An autotroph, or primary producer, is an organism that uses carbon from simple molecules such as carbon dioxide to generate complex organic compounds (such as carbohydrates, lipids, and proteins), typically using energy from light (photosynthesis) or inorganic chemical processes (chemosynthesis). They transform energy from an abiotic source (such as light) into energy stored in organic compounds that can be utilised by other organisms (e.g. heterotrophs). Autotrophs are the producers in a food chain and do not require a live source of carbon or energy, Plants on land or algae in water are examples of this (in contrast to heterotrophs as consumers of autotrophs or other heterotrophs). Autotrophs can use carbon dioxide to produce organic chemicals that can be used in biosynthesis or stored as chemical fuel. Although most autotrophs employ water as a reducing agent, others, such as hydrogen sulphide, can utilize other hydrogen molecules.

Primary producers can use light energy (phototrophs and photoautotrophs) or energy from inorganic chemical substances (chemotrophs and chemolithotrophs) to construct organic molecules, which are then stored as biomass and used as a carbon and energy source by other species (e.g. heterotrophs and mixotrophs). Photoautotrophs are the principal producers, transforming light energy into chemical energy through photosynthesis and eventually constructing organic molecules from inorganic carbon dioxide. Some archaea and bacteria (unicellular organisms) that produce biomass by oxidising inorganic chemical compounds are chemolithotrophs. Chemoautotrophs are commonly found in hydrothermal vents in the deep ocean. Primary producers are the lowest trophic level and are responsible for the continued existence of life on Earth. 

Most chemoautotrophs are lithotrophs, meaning they use inorganic electron donors and hydrogen sources such hydrogen sulphide, hydrogen gas, elemental sulphur, ammonium, and ferrous oxide for biosynthesis and chemical energy release. Autotrophs decrease NADP+ to NADPH to generate organic molecules using a portion of the ATP produced during photosynthesis or the oxidation of chemical substances. 

History

Albert Bernhard Frank, a German botanist, created the word autotroph in 1892.  [a secondary source is required] It comes from the Greek word o (troph), which means “nutrition” or “food.” Around 2 billion years ago, the first autotrophic organism appeared. By creating photosynthesis, photoautotrophs emerged from heterotrophic bacteria. Hydrogen sulphide was utilised by the first photosynthetic microorganisms. Because hydrogen sulphide is scarce, certain photosynthetic bacteria have evolved to utilise water for photosynthesis, resulting in cyanobacteria. 

Variants

Some species rely on organic materials for carbon, but they can also get energy from light or inorganic substances. Mixotrophs are organisms that eat both plants and animals. A photoheterotroph is an organism that derives carbon from organic molecules but obtains energy from light, whereas a chemolithoheterotroph obtains carbon from organic compounds and energy from the oxidation of inorganic substances.

Some fungi have been detected growing inside a reactor at the Chernobyl nuclear power plant, indicating that they may be able to receive energy from ionising radiation.

Examples

There are many distinct types of primary producers at various stages of development across the Earth’s ecosystem. Decomposers are fungi and other organisms that obtain their biomass by oxidising organic materials. They are not primary producers. Lichens in tundra temperatures, on the other hand, are an unique example of a primary producer that combines photosynthesis by algae (or furthermore nitrogen fixation by cyanobacteria) with the protection of a decomposer fungus through mutualistic symbiosis. Plant-like primary producers (trees, algae) also use the sun as a source of energy and release it into the air for the benefit of other organisms.  Of course, there are H2O primary producers, such as bacteria and phytoplankton. Coral and one of the many varieties of brown algae, kelp, are two of the most common examples of primary producers. 

Photosynthesis

Photosynthesis is the process that produces gross primary output. This is also one of the most common ways for primary producers to extract energy and produce/release it elsewhere. This is something that plants, coral, microbes, and algae do. Primary producers extract energy from the sun and convert it to energy, sugar, and oxygen during photosynthesis. Primary producers also require energy in order to turn this energy into something else, thus they obtain it from nutrition. 

The autotrophic primary generation of plants and cyanobacteria that collect photons emitted by the sun supports most ecosystems. Plants can only use a fraction of this energy (about 1%) for photosynthesis.  The photosynthetic process divides a water molecule H2O).releasing oxygen into the atmosphere, and reducing carbon dioxide CO2 to release hydrogen atoms that power the primary production metabolic process. During photosynthesis, plants convert and store photon energy in the molecular bonds of simple sugars. 

Conclusion

An autotroph is an organism capable of manufacturing its own nourishment. Autotrophic organisms absorb inorganic material into their bodies and turn them into organic sustenance. Autotrophs are crucial to all life since they are the primary producers at the base of all food chains. There are two sorts of autotrophs, separated by the energy each takes to produce food. Photoautotrophs use light energy; chemoautotrophs use chemical energy.

Photoautotrophic organisms (e.g., green plants) have the capacity to exploit solar radiation and acquire their energy directly from sunshine.

Until recently, experts maintained there existed just a few kinds of bacteria that used chemical energy to manufacture their own food. Some of these bacteria were identified dwelling near vents and active volcanoes on the lightless ocean floor. The bacteria manufacture their nourishment utilising inorganic sulphur compounds streaming out of the vents from the scorching interior of the planet.

In 1993, scientists uncovered many new kinds of chemoautotrophic bacteria dwelling in foliated rock far below the ocean floor. These bacteria take in carbon dioxide and water and use the chemical energy in sulphur compounds to perform metabolic enzymes that make carbs and sugars. A remarkable trait of these chemoautotrophic bacteria is that they survive at temperatures high enough to kill other species. Some scientists suggest that these unusual bacteria should be classified in their own distinct taxonomic kingdom.