Welcome back, guys. So today we’ve something interesting associated with deep-sea bacteria and their metabolism. So wasting no time, let us move on to what scientists have discovered that’s of so much interest to us.
Scientists have found curious bacteria on the ocean floor, which has a metabolism we’ve never seen before. As Scientists from Germany say, these bacteria called Acetobacterium woodii also lives in the intestines of termites. This can both create and use hydrogen and carbon dioxide to provide energy all on its own, even without the necessity for oxygen.
It’s their ability to survive on organic and inorganic substances alike without oxygen is what makes this bacterium unique and different from other microorganisms. There have been predictions that already such a kind would exist, it’s never been clearly described among acetogenic bacteria, which produce methane free from oxygen.
Microbiologist Volker Müller from Goethe University Frankfurt explains “There have already been speculations that many ancient life forms possess the kind of metabolism that we’ve described in A. woodii,”.
Hydrothermal vents were only discovered in the late ‘70s, and since then we’ve come to understand these strange habitats are home to complex and dynamic forms of life, including mats of bacteria several centimetres thick, which feed on inorganic compounds like hydrogen and sulphide, as they rush up through the subsurface.
There’s a good possibility that this could be one of the largest reservoirs of diverse hydrogen-converting microorganisms in the world, thus it’s thought several creatures may have metabolic systems unlike anything we have seen before.
Even though excess hydrogen inhibits the fermentation process, and even the weakest hydrothermal vents easily exceed the levels needed to harbour fermentative bacteria, the solution lies in sticking together.
It is interrelated as a bacterium that produces hydrogen teams up with another which oxidizes hydrogen.
This new research reveals that bacteria can play both roles in one bacterial cell. In contrast, A. woodii combines the metabolic features of two syntrophic partners in one bacterial cell, the authors of the analysis concluded. Depending on the environmental conditions, A. woodii can play a part of the fermenting partner or the hydrogen consuming partner.
Although it’s still unclear for scientists as they postulate one pathway ferments organic substrates into acetic acid, alcohols, and molecular hydrogen, while another pathway acts as an ‘electron sink’ for the exterior environment, making fermentation energetically possible by forming acetic acid from CO2 and hydrogen.
This double metabolism could exist in other bacteria, but it’s rare and A. woodii has a lower hydrogen threshold. It cannot produce as much energy from converting CO2 to methane as methanogenic archaea.
“Though the ‘hydrogen recycling’ we discovered, A. woodii possesses a maximum of metabolic flexibility,” says one of the team, molecular microbiologist Anja Wiechmann.
“In one cycle, it can both create and use hydrogen itself, or utilise hydrogen from external sources.”
The study was published in the ISME Journal.