After studying the role of iron sulphide in chemical reactions that could lead to the origin of life on our planet, an international team of researchers discovered the processes that contribute to the transformation of carbon dioxide (CO2) into ancient organic molecules under laboratory conditions. hot springs. The discovery will help explain the origin of molecules that are the precursors of life and will also be useful to astrobiologists.

When life on Earth was just beginning, hot springs and minerals containing iron sulfide (FeS) may have played an important role in its emergence. This inorganic compound is known for its ability to accelerate chemical reactions and is similar to coenzymes involved in modern biochemical processes.

Therefore, in 1988, the German jurist and chemist Günter Wechtershäuser put forward the hypothesis of a world of iron sulphides; Accordingly, the first organism on Earth emerged from a volcanic hydrothermal flow (at high temperature (100°C) and high pressure). ) on the surface of sulfur crystals. This life form, which had a complex chemical structure, used catalytic centers based on transition metals such as iron and nickel (and possibly zinc, cobalt, manganese and tungsten).

However, the role of iron sulphides in the conditions prevailing in ancient times is hot sources are still not sufficiently examined.

A team of scientists led by Jingbo Nan from the Nanjing Institute of Geology and Paleontology (PRC) and Martin J. Van Kranendonk from the University of New South Wales (Australia) modeled the environment of ancient hot springs in the laboratory. This allowed them to study in detail the role of iron sulfides in carbon fixation during the early stage of the evolution of life.

Using an anaerobic chamber and gas chromatography (physical-chemical separation method), the researchers synthesized a series of nanosized iron sulfides from mackinawite, including pure iron sulfide and iron sulfides enriched in common elements from hot springs (marga).

Scientists found that at 120°C, manganese-enriched iron sulfide increased methanol (CH₃OH) production fivefold compared to pure iron sulfide. Recall that methanol is a simple organic molecule that can serve as a building block for more complex compounds.

The catalytic activity of iron sulfide was also increased by exposure to ultraviolet and visible light. This is important because at the beginning of life, solar radiation was likely more intense and played an important role in chemical processes on the planet’s surface. Thus, experiments and theoretical calculations carried out under laboratory conditions showed that the intermediate product resulting from the reverse reaction of the “water-gas” transition is carbon monoxide (CO), which subsequently turns into methanol.

The discovery will help understand how simple inorganic compounds can turn into organic molecules without the participation of living organisms, explain the emergence of the first molecules that were the precursors of life on Earth, and even identify the conditions that contributed to this. The results could be useful for astrobiologists to search for life on other planets with similar conditions.