Synthetic biology breakthrough fixes CO2 from the air better than nature

Synthetic biology breakthrough fixes CO2 from the air better than nature
Vials where the new THETA cycle of CO2 fixing is being tested
Vials where the new THETA cycle of CO2 fixing is being tested
View 1 Image
Vials where the new THETA cycle of CO2 fixing is being tested
Vials where the new THETA cycle of CO2 fixing is being tested

Scientists at the Max Planck Institute have developed a synthetic pathway that can capture CO2 from the air more efficiently than in nature, and shown how to implement it into living bacteria. The technique could help make biofuels and other products in a sustainable way.

Plants are famous for their ability to convert carbon dioxide from the air into chemical energy to fuel their growth. With way too much CO2 in the atmosphere already and more being blasted out every day, it’s no wonder scientists are turning to this natural process to help rein levels back in, while producing fuels and other useful molecules on the side.

In the new study, Max Planck scientists developed a brand new CO2-fixation pathway that works even better than nature’s own tried-and-true method. They call it the THETA cycle, and it uses 17 different biocatalysts to produce a molecule called acetyl-CoA, which is a key building block in a range of biofuels, materials and pharmaceuticals.

The cycle is built around the two fastest known CO2-fixing enzymes – crotonyl-CoA carboxylase/reductase and phosphoenolpyruvate carboxylase, for those playing at home – which were isolated from bacteria. Even though each of these alone is more than 10 times faster at capturing CO2 than the primary enzyme plants use, evolution doesn’t seem to have naturally paired them up yet. So, the scientists did instead.

First, the team constructed the THETA cycle in test tubes to confirm its functionality, of capturing two CO2 molecules from the air and converting them into one acetyl-CoA molecule. Then, the researchers optimized it over several rounds of experiments to boost its yield 100 times over. Finally, they set about incorporating the cycle into living cells – namely, E. coli.

The 17-step process is currently too complicated for one cell to handle, so the team split it up into three modules and incorporated these into E. coli. Sure enough, each module worked as hoped. The next step is to squeeze it all into one, but this will require synchronizing each step with the natural metabolism of E. coli.

In the meantime though, this milestone is still important, the team says. The technique could be adapted to instruct microbes to produce a whole range of valuable compounds.

“What is special about this cycle is that it contains several intermediates that serve as central metabolites in the bacterium's metabolism,” said Shanshan Luo, lead author of the study. “This overlap offers the opportunity to develop a modular approach for its implementation. Our cycle has the potential to become a versatile platform for producing valuable compounds directly from CO2 through extending its output molecule, acetyl-CoA.”

The research was published in the journal Nature Catalysis.

Source: Max Planck Institute

People are afraid of geoengineering by injecting aerosols into the atmosphere but not afraid of this… I fully grasp that I might not know enough and that this might not be a big deal, but the idea of creating a microbe that could vacuum up CO2 in significant amounts, escape into the wild and deplete too much, plunging us into an ice age we cannot prevent, is a little bit scary, much scarier than throwing a bunch of particles into the air that will settle out in a few years at most…
Nice article Michael. I think anything that alters the CO2 levels in the atmosphere and oceans easily with some constraints would be a wonderful breakthrough. We already have yeast that does the reverse, releasing CO2 into our dough as we make bread. I am not sure if E coli is the best vehicle for this, but there are a plethora of biological powerhouses that don't currently infect humans or most mammals that could be cultivated - and possibly rate limited by some common switch that must be continuously enabled. Although "The sky is falling" isn't where I would go with successful proof of concept approaches - it does appear seeding the upper atmosphere with microplastics to block solar radiation could be a geoengineering toward an apocalypse. I don't see these microbes in that way!
@Ric...yeah exactly. However, every geoengineering action we take will ultimately need to be fixed further in the future.
Hmmm, the concept of, "What could possibly go wrong?" needs some attention here. A bio-engineered, very common species of bacteria which is a glutton for CO2 couldn't POSSIBLY escape the lab and "get friendly" with "native" forms of the same species . . . or could it????????
@Ric Indeed, noxious and hypoxia driving slimes and bacterias lead to the worst mass extinction events in Earth history. Fools will do anything for a grant.
Treon Verdery
Great research, and very interesting. It encourages me to think that complementary similar genetics that makes humans live to age 560-700 could be just as rapidly developed by a similar size group of a few scientists. For example, the e. coli are using new carbon dioxide modifying enzymes. At humans, ovaries, and particularly oocytes use ATP citric acid cycle II, rather than the human body's usual ATP citric acid cycle I. because cycle two produces lots less oxidative radicals, and possibly other free radicals and is much gentler to human cytes like oocytes that utilize system II, oocytes, and possibly other ovarian cytes live 7 times longer than other body cytes with about a half century cytolifespan per mitosis generation. If every cyte at the human body lived 7 times longer, a 70-100 year human 20th century lifespan then rises to be a 490-700 year human lifespan. The genetic optimization of citric acid cycle II enzymes and molecular participants is likely a similar research and development process to the co2 chemistry optimization described at the article. Also, the citric acid cycle II physiochemistry likely differs at different species. perhaps there is a citric acid cycle II 99.9998th percentile of causing greater cyte longevity that is greater than 7 times heightened multiplier of cyte lifespan. If that multiplier is 11 or 14, then that generates 770-1400 year human lifespan.
Not in my back yard, if you don't mind!