Chemosynthesis. What is chemosynthesis and how does it take place?

In the soil we can find some species of autotrophic bacteria and archaebacteria, that is, bacteria that produce their own food through the chemosynthesis. But what is chemosynthesis?

THE chemosynthesis is a process in which organic matter is produced from carbon dioxide, water and other inorganic substances (such as ammonia, iron, nitrite and sulphur), without the use of energy luminous. As it does not need light energy, this type of bacteria can carry out the chemosynthesis in environments devoid of light and organic matter, since the energy used in its development is obtained through inorganic oxidation.

Examples of bacteria that carry out the chemosynthesis are the genus beggiatoaand Thiobacillus, also called sulfobacteria, as they carry out their metabolism through the oxidation reactions of sulfur compounds.

Another example of chemosynthetic bacteria, also called nitrobacteria, are bacteria of the genus nitromonas and Nitrobacter, very important for the environment and for human beings.

. These bacteria are found in soil and play an important role in recycling nitrogen on our planet. Bacteria of the genus nitromonas obtain energy through the oxidation of the ammonium ion (NH₄⁺), which is present in the soil, transforming it into nitrite ion (NO^-₂); while bacteria of the genus Nitrobacteroxidize the nitrite ion (NO^-₂), transforming it into nitrate ion (NO^-₃), which is taken up by plant roots and used in protein synthesis.

In the process of chemosynthesis we can highlight two distinct steps:

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First step: in the oxidation of inorganic substances, there is the release of protons and electrons that cause the phosphorylation of ADP to ATP and the reduction of NADP⁺ in NADPH, which will be useful in the next phase. Thus, we can conclude that, unlike photosynthesis, a process in which electrons and protons are obtained through the degradation of the water molecule, in chemosynthesis they originate from the oxidation of inorganic substances.

Second stage: through the process of oxidation of inorganic substances, bacteria get enough energy to reduce carbon dioxide through of its fixation and subsequent production of organic substances, which can be used in the production of new compounds or in their metabolism.

In 1977, scientists discovered animals (anemones, clams, crabs and a species of mouthless worm) that could reach more. two meters long, approximately 2.5 km below the surface (a region where there is no trace of luminosity). As all these animals were close to hydrothermal vents (hot water with dissolved hydrogen sulphide), scientists have concluded that this gas is oxidized by chemosynthetic bacteria that transform it into sulfur. Thus, when getting energy to produce organic matter, this type of bacteria served as food for the heterotrophic beings that inhabit the depths, giving that community a chance existed.

By Paula Louredo
Graduated in Biology

Would you like to reference this text in a school or academic work? Look:

MORAES, Paula Louredo. "Chemosynthesis"; Brazil School. Available in: https://brasilescola.uol.com.br/biologia/quimiossintese.htm. Accessed on June 28, 2021.