Cellular powerplant recycles waste gases
The idea is to use the power of bacteria to turn toxic waste gases into valuable compounds such as acetate or ethanol
© Max Planck Institute for Marine Microbiology/T. Wagner
Waste gases of many branches of industry – for example in steel mills – contain mainly carbon monoxide and carbon dioxide. Nowadays, these harmful and greenhouse gases are simply blown into our atmosphere, but this may soon change. The idea is to use the power of bacteria to turn toxic waste gases into valuable compounds such as acetate or ethanol. These can be used afterwards as biofuels or basic compounds for synthetic materials. The first real-size test plants are already under evaluation, using this conversion at an industrial scale, and the stars of these process are bacteria that devour carbon monoxide, carbon dioxide and dihydrogen, among which Clostridium autoethanogenum is by far the favorite.
“In this microbe, the main lines of the metabolism used to operate the gas conversion have been characterized,” says Tristan Wagner, leader of the group Microbial Metabolism at the Max Planck Institute for Marine Microbiology. “But there are still a lot of question marks at the molecular level”. The one in focus of the scientists from Bremen: How is the toxic carbon monoxide processed by enzymes at such stunning efficiency?
Big surprise in a crystal
The molecular-level knowledge of the carbon monoxide conversion is derived from studies performed in the species Moorella thermoacetica. This is a convenient and well-studied marine model organism but exhibits a poor ability to detoxify waste gases, unlike Clostridium autoethanogenum. Both bacteria use the same enzyme to convert carbon monoxide: the CO-dehydrogenase/Acetyl-CoA synthase, shortened as CODH/ACS. It is a very common enzyme which existed already in primeval times of the earth. “Since both species use the same enzyme to convert carbon monoxide, we were expecting to see exactly the same structure with eventually minor differences,” says Wagner.
For their research, Wagner and his colleague Olivier N. Lemaire are studying the bacterium Clostridium autoethanogenum to understand how it can thrive at the thermodynamics of Life, using a metabolism similar to that of the first living forms. Olivier N. Lemaire grew the bacteria and purified its CODH/ACS in absence of oxygen, which is detrimental to the enzyme. The two scientists used the crystallization method to obtain crystals of the enzyme CODH/ACS and determine the protein 3D-structure by X-ray crystallography. “When we saw the results, we couldn’t believe our eyes,” says Wagner. “The CODH-ACS interface from Clostridium autoethanogenum drastically differs from the model of Moorella thermoacetica, even though it was the same enzyme and similar bacteria”.
Same ingredients, different architecture
Afterwards, the two researchers carried out further experiments to prove that the first structure was not an artifact but the biological reality. Following experiments confirmed the initial model. Thus, the discovery clearly proves wrong the previous assumption that the enzyme CODH/ACS always has the same overall structure. “The enzyme of Moorella thermoacetica has a linear shape,” explains Olivier N. Lemaire, first author of the study, which was recently published in the scientific journal BBA Bioenergetics. “In Moorella thermoacetica, the enzyme produces carbon monoxide in the CODH and uses in the ACS. Between them, it is trapped and funneled through a sealed gas-channel. ACS will ultimately synthesize acetyl-CoA, a building block further processed into acetate and ethanol. The rest of the cell do not see any carbon monoxide”.
But Clostridium autoethanogenum absorbs carbon monoxide directly. “In Clostridium autoethanogenum the enzyme CODH/ACS has not only one opening, but several. In this way it can collect as much carbon monoxide as possible and conduct it into a whole system of tunnels, operating in both directions”, says Lemaire. “These results show a reshuffling of internal gas-tunnels during evolution of these bacteria, putatively leading to a bidirectional complex that ensures a high flux of carbon monoxide conversion toward energy conservation and assimilation of carbon monoxide, acting as the main cellular powerplant”. At the end of the process also acetate and ethanol are generated, which can be used to produce fuels.
“We now have a picture of what this very efficient and robust enzyme looks like”, says Tristan Wagner. “But our discovery is only one step further. Among other things, it is still an open question how the bacterium can survive and use carbon monoxide to feed their whole cellular energy needs. We have some hypotheses, but we are still at the beginning. To understand the whole chemical process of converting carbon monoxide to acetate and ethanol, further proteins need to be studied”.
Other news from the department science
Blue-green algae sugar instead of glyphosate
Cooperation project develops environmentally friendly glyphosate alternative
Using clay to combat eternal toxins
TU Freiberg clarifies basis for innovative PFAS filter made of clay
Unveiling a new era of imaging: Boston University engineers lead breakthrough microscopy techniques
Researchers made significant advancements in the field of vibrational imaging
Phasing out fossil fuels could save millions of lives
The mortality burden attributable to air pollution from fossil fuel use is considerably higher than most previous estimates - a phaseout of fossil fuels would have tremendous, positive health outcomes
Replicating the structure of bird feathers
The new material could be used in batteries or filtration
Quantum tool opens door to uncharted phenomena
Method can contribute to a better understanding of quantum materials
Recovering instead of shredding: recycling batteries more efficiently
KIT researchers are working with industry to develop a more sustainable recycling process to recycle materials from lithium-ion batteries more effectively
Industry 4.0: No impact on energy consumption?
To what extent does the digitalisation of industrial and manufacturing processes (Industry 4.0) improve energy efficiency and thus reduce energy intensity?
New approach to the sensible utilisation of carbon dioxide from car exhaust gases
"A method has been discovered that uses impure CO2 streams and enables a breakthrough in the synthesis of valuable chemicals and pharmaceuticals"
Boosting PET recycling with higher standards for laboratory experiments
New study shows how enzymatic plastic degradation could be brought one step closer to commercialisation
Innovating Optoelectronic Components with Phosphorus
Significant breakthrough: phosphorus chemists develop new method to selectively introduce phosphorus and nitrogen atoms into polyaromatic systems
Artificial intelligence finds ways to develop new drugs
The chemists tested the process using borylation – a reaction that activates hydrocarbon scaffolds
X-rays reveal how glasses lose their stability
PETRA III experiment shows how atoms in glass behave as weaknesses appear
Most read news
Plastic-eating bacteria turn waste into useful starting materials for other products
Microbial Upcycling of Waste PET
Microbes could help reduce the need for chemical fertilizers
A coating protects nitrogen-fixing bacteria: Start-up to commercialise coated bacteria for large-scale use in regenerative agriculture
New designs for solid-state electrolytes may soon revolutionize the battery industry
Scientists achieve monumental improvements in lithium-metal-chloride solid-state electrolytes
Dow and Evonik announce startup of hydrogen peroxide to propylene glycol (HPPG) pilot plant
Innovative technology offer flexibility, lower costs, and a smaller environmental footprint
Inauguration of the world’s first pilot plant for the cost-efficient production of green methanol
Start-up C1 Green Chemicals AG and research partners develop fundamentally new production process
This is a battery
Two colored liquids bubbling through tubes: Is this what the battery of the future looks like?
Converting PFAS “forever chemicals” into valuable compounds
Scientists develop a new method to incorporate harmful perfluoroalkenes into N-heterocyclic carbene ligands
Not so silver lining: Microplastics found in clouds could affect the weather
Low-altitude and denser clouds contained greater amounts of microplastics
Graphene's proton permeability: A switch for future energy technologies
This discovery could lead to the development of more efficient hydrogen fuel cells and solar water-splitting devices
Lithium-ion batteries are no longer the gold standard in battery tech
On the way to safer and more powerful energy sources
CO2-free hydrogen: BASF receives funding approval for 54-megawatt water electrolysis plant
Proton exchange membrane (PEM) electrolyzer expected to produce up to 8,000 metric tons of hydrogen per year
More news from our other portals
Bowel cancer: aspirin activates protective genes
Researchers have identified a signaling pathway by which aspirin can inhibit colorectal cancer.
Dunning-Kruger effect with muesli bars
Those who know the least consider themselves highly competent
Autonomous measuring instruments systematically detect new materials
A new algorithm measures materials libraries up to four times faster than before: It’s based on machine learning
New drug delivery system could reduce daily diabetes shots to just three a year
Dietary management drugs have transformed Type 2 diabetes care, but daily injection routines are challenging for some patients
Naked Clams: The New Superfood Sensation Emerging from the Depths
Researchers found Naked Clams contain almost twice the amount of Vitamin B12 as blue mussels and have developed an efficient way to farm them
Researchers discover new ultra strong material for microchip sensors
A material that doesn't just rival the strength of diamonds and graphene, but boasts a yield strength 10 times greater than Kevlar
Pushers, overcrowded trains and phone zombies
Sprite presents the world's first vending machine that responds to the things that bother Generation Z the most
Aston University technology to combat the not-so sweet practice of honey fraud
Light technology to be used to detect if honey is blended with cheap additions
How stem cells and immune cells communicate
Lisec Artz Award for Simon Haas: Groundbreaking discovery of an unknown protective mechanism against blood cancer from stem cells
Scientists use quantum biology, AI to sharpen genome editing tool
"This study represents an exciting advancement toward, understanding how we can avoid making costly ‘typos’ in an organism’s genetic code"
From the trough to the plate - digitally calculated
Computer program "ConTrans" estimates how much of an undesirable substance is transferred from animal feed to food
Viral Impostors: Breakthrough for Virus Research
The penetration of viruses into cells can now be tracked with unprecedented accuracy thanks to innovative design for pseudoviruses
Fatty acid factory filmed at work
High-resolution images provide new insights into cellular fatty acid production: Potential for medicine and biotechnology
Textbook knowledge turned on its head: 3-in-1 microorganism discovered
Newly multifunctional bacterial species
Tönnies Group launches first nationwide "Meat Climate Platform"
100 guests at the Future Forum for Agriculture
Tracking down Environmental Toxins
Detection of per- and polyfluoroalkyl substances (PFAS) by interrupted energy transfer
Could eating turkey ease colitis?
According to data in mice, extra tryptophan could reduce the risk of future colitis flares
The weight of pollution: exposure linked to obesity
Chronic exposure to environmental pollutants found to increase risk of cardiovascular disease
Are healthy foods automatically sustainable, too?
Perceptions about sustainability and healthy food choices are closely linked