Researchers engineer photosynthetic bacteria to produce hydrogen:
The price of photovoltaic power has plunged, making it competitive with fossil fuel-powered electrical generation. But there is still a range of applications, like ships and aircraft, where electrical power doesn't help much. And storing the electricity produced by solar power so that it can be used at night remains an unsolved problem. For those reasons, there's been continued interest in converting solar power to a fuel that can be stored, either through the use of electricity generated by photovoltaics or by using light to directly power fuel generation.
There's obviously a means of generating fuel through light that's been in use for roughly 3 billion years: photosynthesis. But photosynthesis requires a large and complex suite of proteins that's hard to maintain outside of cells. And inside of cells, the products of photosynthesis are quickly put to use to help the cells grow. So, engineering a version of photosynthesis that might be useful for fuel production has been challenging.
Earlier this week, however, researchers from the University of Kiel described how they've rearranged some photosynthetic proteins to make bacteria that emit hydrogen when exposed to light.
[...] The engineered cyanobacteria produced the highest levels of hydrogen yet seen in these organisms, and they could continue producing hydrogen for hours. Presumably, they'd eventually scavenge enough hydrogen ions from the solution they were growing in to change its pH, but this didn't seem to be a problem during several hours of illumination.
The researchers behind the work say there are a number of ways they can potentially improve the flow of electrons within their engineered complex. And, ultimately, it would be ideal to make the process less sensitive to oxygen in general.
But they argue that their approach provides a big benefit over previous efforts in this area. Many of these have focused on removing the photosynthesis components from a living cell in order to precisely control the pathways that are active in order to bias production toward hydrogen or other fuels. But, outside the cell, these components quickly pick up damage and can't be replaced. Alternatives that operate in an intact cell face the challenge of keeping the cell from diverting energy into the pathways it needs for rapid reproduction. This work, the researchers argue, confirms that you can have the benefits of working in living cells while at the same time engineering away some of those competing pathways.
Journal Reference
Jens Appel, Vanessa Hueren, Marko Boehm, et al. Cyanobacterial in vivo solar hydrogen production using a photosystem I–hydrogenase (PsaD-HoxYH) fusion complex, Nature Energy (DOI: 10.1038/s41560-020-0609-6)
(Score: 1, Informative) by Anonymous Coward on Wednesday May 13 2020, @12:07PM (2 children)
> So, engineering a version of photosynthesis that might be useful for fuel production has been challenging.
Easy -- let the trees grow, burn the wood for energy. It's been in use since the "domestication" of fire.
(Score: 2) by DeathMonkey on Wednesday May 13 2020, @05:31PM (1 child)
Easy -- let the trees grow, burn the wood for energy, then die ten years early from lung disease.
(Score: 0) by Anonymous Coward on Wednesday May 13 2020, @11:10PM
We've gotten more sophisticated, about 30 years ago my friends that heat (partially) with wood added a catalyst to their stove, cleans up at least some of the nasty exhaust. Because the catalyst is burning stuff that would have gone up the stack, they get more heat from the wood too.
(Score: 0) by Anonymous Coward on Wednesday May 13 2020, @12:18PM
one assumes that if this works, that not before long a "invasion off bacteria tanks, virus airplanes and navy" will lay waste to these colonies (providing "free energy").
furthermore the real challenge might be engineering a working "immune system" for these hydrogen liberating bugs?
(Score: 2) by EvilSS on Wednesday May 13 2020, @02:43PM (1 child)
I get there are new ways being researched to store excess power output from renewables for peak or overnight uses, but calling it "unsolved" is pretty bold. We have a number of options today, from battery storage (such as the Tesla deployment Australia) to old fashioned pump-storage hydro.
(Score: 2) by crafoo on Wednesday May 13 2020, @03:40PM
Maybe they just mean unsolved in the sense of the economics and scaling of these existing technologies. I think that's probably the most favorable interpretation?
(Score: 2) by HiThere on Wednesday May 13 2020, @04:08PM (4 children)
Engineer bacteria to produce gasoline and you've got something worthwhile. This idea seems a cross between stupid and dangerous. It's only dangerous, of course, if the bacteria can survive in the wild, but since hydrogen leaves the planet, that could be a good way to get rid of all that water. Oops! (Yes, it would take awhile. So?)
Gasoline is useful. Hydrogen is only useful in chemical processing plants and rocket engines. (Well, I exaggerate for rhetorical purposes.) For mobile air-breathing engines gasoline is far better. The fuel storage is more compact and less explosive. And less expensive. The main thing wrong with gasoline is that it's derived from fossil carbon...and brewing it up today would remove that problem. There's probably an optimum chain link, of course, and perhaps gasoline doesn't quite hit it. Acetylene is too energetic to handle safely in quantity, but it's better than hydrogen for most purposes. Probably the best fuel would be a chain with alternating double and single bonds about (wild guess) eight atoms long. I'm clearly speculating well past my level of expertise here, though. But if they could make something *like* gasoline it would be a lot better.
Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.
(Score: 0) by Anonymous Coward on Wednesday May 13 2020, @11:15PM
> Probably the best fuel would be a chain with alternating double and single bonds about (wild guess) eight atoms long.
Something like this? https://en.wikipedia.org/wiki/Octane [wikipedia.org]
Pure 2,2,4-trimethylpentane (a highly branched octane) has an "octane rating" of 100, so it's clearly good for gasoline engines (although some lighter components might be needed for starting in wintertime?)
(Score: 2) by PartTimeZombie on Thursday May 14 2020, @02:10AM
We've done this before, and those cyanobacteria killed everybody. [wikipedia.org]
(Score: 2) by Rich on Thursday May 14 2020, @07:37AM (1 child)
https://en.wikipedia.org/wiki/Acetone%E2%80%93butanol%E2%80%93ethanol_fermentation [wikipedia.org]
As you say, if you set out to bio-engineer fuel production, it will be an easier path for storage, transportation, and use, to go straight to hydrocarbons. Even methane would be good enough (and actually best from an emissions view with ICEs and residential heating, bonus points for combined cycle electricity with the latter).
That made me think, could cow farts (and related stuff) be sequestered and put to better use than as a greenhouse gas?
(Score: 2) by HiThere on Thursday May 14 2020, @03:20PM
No, methane wouldn't be good enough, though if it would there would be no reason to do any gengineering, as already existing microbes are pretty good at that. Ethane would be good enough, though slightly longer would be better.
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