As the world transitions to green hydrogen and other renewable energy sources, scientists believe that archaea third form of life For billions of years, bacteria and eukaryotes have used hydrogen gas and ‘ultra-minimal’ enzymes to create energy.
Specifically, the international research team discovered that there are at least nine phyla. archaeaa region of single-celled organisms without internal membrane-bound structures, produce hydrogen gas using enzymes thought to exist only in the other two forms of life.
They found that Archaea not only have the smallest hydrogen-using enzymes compared to bacteria and bacteria. eukaryoteHowever, the enzymes that consume and produce hydrogen are the most complex yet characterized.
These small, powerful enzymes appear to allow archaea to survive and thrive in some of the most hostile environments on Earth, where little or no oxygen is found.
“Humans have only recently started thinking about using hydrogen as an energy source, but archaea have been doing it for billions of years.” Called Pok Man Leung, a microbiologist at Monash University in Australia who co-led the study, said:
“Bioengineers now have the opportunity to take inspiration from these archaea to produce hydrogen industrially.”
Hydrogen is the most abundant element in the universe, used worldwide They make fertilizers and other chemicals, process metals, process food, and refine fuels.
But the future of hydrogen depends on energy storage and steel manufacturing, where it can be produced without emissions. If you use renewable energy Converts substances such as water into hydrogen gas.
microbe Hydrogen gas (H2) It has a completely different purpose, mainly to dispose of the excess electrons generated. fermentationThe process by which an organism extracts energy from carbohydrates, such as sugar, without oxygen.
Enzymes used to consume or produce H2 will be called hydrogenaseAnd for the first time, they have been comprehensively surveyed across the tree of life. just 8 years ago. Since then, the number of known microbial species has exploded, especially archaea, which lurk in extreme environments such as hot springs, volcanoes, and deep-sea vents.
However, most archaea are known only from chunks of genetic code found in these environments, and most have not been cultured in the laboratory because they are very difficult to culture.
So Monash University microbiologist Chris Greening and colleagues searched for genes that encode a type of fast-acting hydrogenase. [FeFe] Hydrogenases included in a cluster of more than 2,300 archaeal species listed in global databases.
They then tasked Google’s AlphaFold2 with predicting the structure of the encoded enzyme, which they expressed as follows: E. coli The bacteria sought to determine whether the gene was actually functional and produced a hydrogenase that could catalyze the hydrogen reaction in a surrogate host.
“Our discovery brings us one step closer to understanding how this important process gave rise to all eukaryotes, including humans,” Leung said. Called.
Eukaryotes are organisms whose cells contain a nucleus and membrane-enclosed organelles such as mitochondria and other useful cell factories.
All eukaryotes are thought to have emerged from the union of anaerobic archaea and the bacteria they engulfed billions of years ago. A second, much later endosymbiosis gave rise to the ancestors of plants, including chloroplasts.
Greening, Leung and their colleagues discovered the following genetic instructions: [FeFe] Hydrogenases from nine archaeal phyla were identified and confirmed to be indeed active in these microorganisms. That means there are three domains of life that use these types of enzymes to make hydrogen.
But unlike bacteria or eukaryotes, further analysis showed that archaea assemble “remarkable hybrid complexes” by fusing two types of hydrogenase to suit their hydrogen production needs.
“These findings reveal a new metabolic adaptation in archaea, streamlined H.2 A catalyst for biotechnological advances, and the surprisingly intertwined evolutionary history between the two major H2-Metabolic Enzymes” Research Team write on their papers.
However, many of the lists of archaeal genomes analyzed in this study are incomplete, and who knows how many more species there are yet to be discovered.
It is likely that archaea harbor other ingenious ways of making energy that we have not yet discovered.
This study was published in: cell.
