from Hacker News

Scientist Engineers Bacterium That Inhales CO2, Produces Energy

by miraji on 5/30/16, 2:15 PM with 91 comments

by Turing_Machine on 5/30/16, 2:59 PM
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.
by fabian2k on 5/30/16, 2:45 PM
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.
by smaili on 5/30/16, 2:39 PM
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.”
by goda90 on 5/30/16, 2:50 PM
"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.
by johngalt on 5/30/16, 11:30 PM
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.
by riprowan on 5/30/16, 5:10 PM
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.
by shaqbert on 5/30/16, 2:50 PM
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.
by kbutler on 5/30/16, 5:15 PM
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... says about 1 kg, which works out to about 560L CO2 http://www.umsl.edu/~biofuels/Energy%20Meter%20labs/How%20mu...)
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?
by dTal on 5/29/16, 4:03 PM
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!
by xfactor973 on 5/30/16, 3:55 PM
If you burn the alcohol and bury the biomass then you're carbon negative. This needs to get put into production immediately!
by thereisnospork on 5/31/16, 5:45 AM
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.
by JustUhThought on 5/30/16, 3:18 PM
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
by abhi3 on 5/30/16, 3:40 PM
>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.
by tener on 5/30/16, 8:27 PM
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.
by gumby on 5/30/16, 4:56 PM
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
by DateK on 5/30/16, 4:58 PM
> 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.
by andrewvijay on 5/30/16, 6:21 PM
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 !
by ommunist on 5/30/16, 7:31 PM
Carbon-neutral bioreactors. Very interesting and extremely useful research. Who shall own that DNA strain and control dissemination of technology?
by smt88 on 5/30/16, 3:57 PM
This announcement is about a year old. I'm not sure why Forbes is covering it like it's news.
by SCHiM on 5/30/16, 4:17 PM
Does this mean our problems with CO2 buildup are partialy solved? Or solved to any large extent?