
Scientist Engineers Bacterium That Inhales CO2, Produces Energy - miraji
http://www.forbes.com/sites/jeffmcmahon/2016/05/29/harvard-scientist-engineers-a-superbug-that-inhales-co2-produces-energy/
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Turing_Machine
The headline, while accurate, doesn't really describe the breakthrough here.

In itself, it's not surprising that sunlight, hydrogen from water and CO2
could be put together to make biomass. That's pretty much what plants (and
many natural bacteria) do already.

The novel aspect of these bacteria is that they apparently do the job 10x more
efficiently than natural organisms.

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amelius
> The novel aspect of these bacteria is that they apparently do the job 10x
> more efficiently than natural organisms.

This makes me wonder why this solution was not found by evolution directly.

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jerf
It's 10x more efficient _for human purposes_. It's not a 10x more efficient
mechanism in general. Evolution has no need to produce 10x more rather energy-
expensive molecules than it needs, so it doesn't produce bacteria that do
that.

Which is also the answer to everybody else wondering about what happens if
this gets into the biosphere. Well, have you ever been walking in a relatively
natural forest area and come across the sad sight of a natural clearing being
totally dominated by wild broccoli plants? No, you never have, because
broccoli is completely incapable of outcompeting any natural plant. Broccoli's
genes put _way_ too much energy into producing that big beautiful edible bit
that all of its competition puts into offense and defense. Similarly, the
answer to the question of what happens to bacteria that pours its energy into
producing alcohol while its competition is pouring its energy into producing
offspring is that if you blink, you'll miss the death of the alcohol-producing
bacteria. They're not going to take over the ecosystem. In energy terms you
probably stand a better chance of seeing broccoli sweep the meadows of the
world than having this bacteria survive in the wild.

(And when I say broccoli, I mean something like what you'd buy in the store.
Not merely a rapid reversion to its historical ancestor, which could actually
happen, but actual proper broccoli.)

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pfarnsworth
> Evolution has no need to produce 10x more rather energy-expensive molecules
> than it needs, so it doesn't produce bacteria that do that.

You don't seem to understand natural selection. The idea of evolution
producing something that an organism "needs" is akin to saying that God
decided that the organism "needed" it and changed its genes.

The theory of natural selection is a completely passive process. For every
generation of an organism, the genes are naturally randomized, producing
various expressions of genes, and once there is selecting event, those that
are not selected for will go extinct. That's what natural selection means. The
idea that a giraffe "needed" a long neck is preposterous because it implies
that the animal willed itself to have a longer neck. Instead, the giraffe's
ancestors had a variable length neck, but given its particular circumstances,
those with longer necks survived, and passed those genes on.

So there very well might be naturally occurring bacteria that produce 10x
efficiently, but they haven't been selected for, yet.

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kbenson
> You don't seem to understand natural selection. The idea of evolution
> producing something that an organism "needs" is akin to saying that God
> decided that the organism "needed" it and changed its genes.

I'm pretty sure he understands it fine, and is just using shorthand that makes
it easier to describe.

There exists no approximation of a fitness function in nature that selects for
this output because it's not efficient for survival, until we come along and
create custom environments and select for survival based on energy output.

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fabian2k
The headline is seriously misleading, the energy comes from sunlight which is
used to split water into hydrogen. And the bacteria use the hydrogen as an
energy source to create biomass from CO2. That biomass is mostly in burnable
fuel.

The article is very interesting, but the headline makes it sound like a
fundamental misunderstanding of thermodynamics.

~~~
gherkin0
> The headline is seriously misleading

I think it's more a difference between technical vocabulary and colloquial
vocabulary. I think a lot of people use the word "energy" to to refer to
something more like "fuel." That's how you get terms like "energy production"
which include activities like drilling for oil.

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smaili
FWIW,

 _“This isn’t solving your CO2 problem,” he said. ”I’m taking CO2 out of the
air, you burn it and you put the CO2 back. So it’s carbon neutral. I’m not
going to reverse 400 ppm of CO2. But you’re not going to use any more stuff
out of the ground.”_

~~~
evunveot
I think he's selling it short. Imagine if all 1 billion+ cars used this fuel
instead of diesel/gasoline. Even if all the carbon ultimately ends up as CO2
again eventually, at any given moment there would be a whole lot of it
temporarily sequestered in fuel tanks. The "base load" of atmospheric CO2
would be lower.

I don't know enough chemistry or climate science to estimate whether the
amount of carbon in ~5 billion gallons of alcohol-based fuel, when removed
from the atmosphere, would have a significant effect on climate change. But it
sure seems like a lot of carbon.

~~~
ams6110
Given that the current level of CO2 in the atmosphere includes the output of
over 100 years of industrial world-wide burning of petroleum and coal, then no
I don't think the amonut of carbon that could be sequestered in current fuel
inventories would make a significant difference. Unless you stockpile decades
worth of fuel.

~~~
sdenton4
Yeah, but it's a hundred years of industrial burn which was growing at an
(approximately) exponential rate; the most recent burn has a much, much larger
impact than the burn in 1916.

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goda90
"The leaf hasn’t lived up to its promise, Nocera said, because the world isn’t
ready for hydrogen fuel."

And probably won't be for transportation because battery tech is improving.
But if this proves to be an effective way to produce liquid biofuel that can
replace gasoline/diesel with simple engine conversions, then we can repurpose
our existing liquid fuel infrastructure and existing cars instead of building
a whole new hydrogen based system.

~~~
shaqbert
Hydrogen fuel is indeed really difficult to manage. The Hindenburg accident
come to mind, or the weight problems of fuel cell cars...

~~~
ams6110
It's the smallest molecule there is. It's really difficult to contain. It will
leak out of steel containers while embrittling the metal. However it's not
necessary to use pure hydrogen as vehicle fuel. Alcohol or other hydrocarbons
can be used directly in a fuel cell to produce electric power, or be burned in
an more traditional combustion engine.

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myrryr
Helium is the smallest molecule. H2 is quite a bit bigger.

~~~
dogma1138
Helium is the smallest atom iirc helium doesn't have a molecule.

~~~
myrryr
the helium atom IS its molecule..

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johngalt
My brilliant invention: A solar powered self replicating machine that eats CO2
and uses it to create building material. With minimal preparation the material
could also be burned for energy.

I wonder how far I'd get before people realized I was planting trees.

~~~
lugg
To be fair, this is 10 times as efficient as plants.

Fwiw, it took me to the third sentence.

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riprowan
My guess is that the chief obstacle will be political: this has the potential
to hit the most powerful people in the world directly in the pocketbook

He's probably going to India probably because there is more political will
there to allow this thing to continue.

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shaqbert
Any mechanism to capture CO2 emissions is a huge win for the environment.

What is missing is an assessment of cost. If this is economically feasible at
some point in time in the future, then goodbye oil and coal.

Open question is how to ensure these bio-engineered organisms don't seep into
the environment and trigger some unintended consequences. There needs to be
some kill switch in there as well.

~~~
rmchugh
He states that the purpose is not carbon capture but energy production, as all
carbon consumed will be released upon combustion.

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dhimes
Carbon neutral combustion is still a win.

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kbutler
500L CO2 per day, to make 2kwh of electricity (per day)

That's approximately as much CO2 as a person breathes out in a day
([https://en.wikipedia.org/wiki/Carbon_dioxide#Human_physiolog...](https://en.wikipedia.org/wiki/Carbon_dioxide#Human_physiology)
says about 1 kg, which works out to about 560L CO2
[http://www.umsl.edu/~biofuels/Energy%20Meter%20labs/How%20mu...](http://www.umsl.edu/~biofuels/Energy%20Meter%20labs/How%20much%20volume%20does%20a%20kg%20of%20CO2%20occupy.pdf))

So yes, it provides a little bit of power, and no, it isn't likely to scale up
to planet-wide CO2 reductions - one per person on the planet just to cover the
CO2 we breathe?

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danielharan
You're comparing completely different things.

It depends first on what is done with the ~1kg of CO2 captured.

If humans get their carbon from sources that are removed from the air, we
don't have a net addition.

~~~
ommunist
Strictly speaking, fossil fuels are carbon removed from the air, just a long
time ago.

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dTal
It sure sounds promising, but it'd be good to see some more efficiency
numbers. All there is in the article is this:

"A one-liter reactor full of Nocera’s bacteria can capture 500 liters of
atmospheric CO2 per day, he said. For every kilowatt hour of energy they
produce, they’ll remove 237 liters of CO2 from the air."

By my reckoning that works out to about 80 watts, continuous. Solar irradiance
is roughly a kilowatt per square meter, so to get 80 watts at 10% efficiency
you need nearly a square meter, which leaves your 1-liter reactor stretched to
a millimeter thick. Hard to imagine a 1mm thick mat of bacteria absorbing 10%
of the light.

The limiting factor really is area, not volume. By that metric, solar panels
are still twice as efficient. Still, it would be good to have solar panels
that grow themselves!

~~~
pmyjavec
It would be nice to put plots of these bacteria on the shady side of roofs.

That way you can store some fuel for cold and rainy days / months :)

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xfactor973
If you burn the alcohol and bury the biomass then you're carbon negative. This
needs to get put into production immediately!

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thereisnospork
I wonder how much of the efficiency increase comes from simply bypassing
photosynthesis (e.g. what is the thermodynamic efficiency of yeast for glucose
-> ethanol)?

In any case there are a few important questions re feasibility. Do these
bacteria work at atmospheric partial pressures of CO2? Do they perform at the
advertised rate at the ~0.0015g/L of hydrogen you'd be lucky to get in
solution from his leaf?

Nocera is a blow hard, so pending the full paper I expect the answers aren't
encouraging.

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JustUhThought
Yay. Now we don't need plants to reduce the greenhouse gas CO2. We just need
to turn loose this bacterium and build an economy around alcohol fuels. No
need for systems thinking that involves the environment when we can create a
bacterium which is more efficient in one aspect of the environment it is
replacing. So long as we can extend this reductionist framework to provide us
with the nitrogen we need. And the global temperature management functions.
And the human food. And the....etc

~~~
jeffwass
The Simpsons is already way ahead, with a similar scenario (lizards getting
rid of the menacing pigeon population) :

SKINNER Well, I was wrong. The lizards are a godsend.

LISA But isn't that a bit short-sighted? What happens when we're overrun by
lizards?

SKINNER No problem. We simply unleash wave after wave of Chinese needle
snakes. They'll wipe out the lizards.

LISA But aren't the snakes even worse?

SKINNER Yes, but we're prepared for that. We've lined up a fabulous type of
gorilla that thrives on snake meat.

LISA But then we're stuck with gorillas!

SKINNER No, that's the beautiful part. When wintertime rolls around, the
gorillas simply freeze to death.

~~~
JustUhThought
Well, it goes without saying, of course the "Simpsons Already Did It". :)

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abhi3
>But if hydrogen from the leaf can combine with CO2 to make alcohol fuel, the
fuel can be used the way diesel is now.

Hmmmm....so bacteria breathes in CO2 to make fuel....so we can burn the fuel
and release the CO2 back in the atmosphere?

Not to take away anything from this impressive scientific achievement but this
application is just depressing.

~~~
ZenoArrow
The application you've described isn't depressing.

Carbon dioxide is a normal element in our atmosphere. Burning biofuels isn't a
problem because the world's ecosystem is used to processing the levels of
carbon dioxide that exist in current circulation.

The problems that come from carbon dioxide in the atmosphere happen when you
alter the levels of carbon dioxide faster than the ecosystem can react. This
happens when burning fossil fuels on a large scale because it leads to adding
more carbon dioxide into standard circulation. As there isn't a proportional
increase in plant life ready to absorb this increase the carbon dioxide can
have negative impacts on our environment, such as ocean acidification.

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tener
Very cool, except first you need to get the hydrogen. For that I believe he is
planning to use the "artificial leaf" he has invented previously.

Problem is, while the bacteria can reproduce on their own, the leafs won't.
They are made from silicon so probably similar tech to regular solar cells.
This can be likely a limiting factor here.

Still interesting news.

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gumby
I can't open the forbes page; how does this compare to Nate Lewis' work at cal
tech (which is a mechanical alternative):
[http://nsl.caltech.edu/research](http://nsl.caltech.edu/research)

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DateK
> the leaf can make hydrogen from any water—dirty water, even urine

I wonder how they tackle the problem of monoculture.

The issue with biofuel from algae is that once the container is contaminated
with fungae, it reqires expensive draining and bleaching.

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andrewvijay
Everyday I think of the suffocating levels of pollution here in India while I
commute. This is a fantastic news for us since they are planning to bring it
up here first !

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ommunist
Carbon-neutral bioreactors. Very interesting and extremely useful research.
Who shall own that DNA strain and control dissemination of technology?

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smt88
This announcement is about a year old. I'm not sure why Forbes is covering it
like it's news.

~~~
pcl
_When Harvard Professor of Energy Daniel G. Nocera announced he was working
with bacteria last year, other scientists cautioned it would be difficult to
achieve a productive level of efficiency. At the time, Nocera was aiming for 5
percent efficiency—about 5 times better than plants. This month at the
University of Chicago, he announced his bug converts sunlight ten times more
efficiently than plants._

This increase in efficiency is presumably the novel part of Nocera's latest
announcement and upcoming paper.

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SCHiM
Does this mean our problems with CO2 buildup are partialy solved? Or solved to
any large extent?

