# Can humans cost effectively synthesize glucose & fructose with solar power **URL:** \ **Category:** Factual Questions\ **Created:** [March 3, 2006, 2:49am UTC](https://boards.straightdope.com/t/can-humans-cost-effectively-synthesize-glucose-fructose-with-solar-power/346861 "2006-03-03T02:49:27Z")\ **Posts on this page:** 12\ **Page:** 1
**Author:** ![Wesley\_Clark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wesley_clark/32/20581_2.png) [@Wesley\_Clark](https://boards.straightdope.com/u/Wesley_Clark)\ **Post date:** [March 3, 2006, 2:49am UTC](https://boards.straightdope.com/t/can-humans-cost-effectively-synthesize-glucose-fructose-with-solar-power/346861/1 "2006-03-03T02:49:27Z")
Do we have artificial photosynthesis that allows us to manufacture glucose and fructose with some kind of energy input (preferably solar power)? I have heard of research into artificial photosynthesis involving transition metals, but that was more for solar panels and not to synthesize sugar. ---
**Author:** ![Blake](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@Blake](https://boards.straightdope.com/u/Blake)\ **Post date:** [March 3, 2006, 4:39am UTC](https://boards.straightdope.com/t/can-humans-cost-effectively-synthesize-glucose-fructose-with-solar-power/346861/2 "2006-03-03T04:39:41Z")
It’s certainly possible enough to synthesise sugars from air and water if you want to. It only requires a [formose reaction](http://www.science.siu.edu/microbiology/micr425/425Notes/14-OriginLife.html). It’s also possible to rig up some solar panels and use the electricity generated to power the lab where you are synthesising the sugars. So in that sense we can manufacture sugars using solar energy. Is it cost effective? No, of course not. If it were people wouldn’t bother to use corn syrup or cane sugar. That is what cost effective means after all. ATM it is so complicated and expensive that nobody bothers to do it at all. I get the impresion that you envision some sort of artificial photosyntheis incorporating a black box. Water an air go in one end and sugars come out the other. We have to produce our sugars step by step with some rather bulky equipment and a refining process at then end of each step. I would imagine that it would be posible to automate the process, but you are still talking about a large room to do this in. ---
**Author:** ![Blake](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@Blake](https://boards.straightdope.com/u/Blake)\ **Post date:** [March 3, 2006, 5:32am UTC](https://boards.straightdope.com/t/can-humans-cost-effectively-synthesize-glucose-fructose-with-solar-power/346861/3 "2006-03-03T05:32:01Z")
“The total synthesis of carbohydrates and analogs has kept chemists occupied since 1861 when Butlerow [1] discovered the formose reaction, which generates mixtures of racemic aldoses and ketoses by oligomerization of formaldehyde in the presence of Ca(OH)2. Currently, with the advent of highly stereoselective and enantioselective methods, almost any natural or nonnatural carbohydrate can be readily obtained from inexpensive starting materials in an enantiomerically pure form. D-Glucose, D-mannose, D-glucosamine, D- and L-arabinose from natural sources, are certainly cheaper than those from total synthesis. However, when dealing with unnatural enantiomers of common carbohydrates, or with unusual derivatives in which hydroxy groups are replaced by other functionalities (amino-, alkoxy-, thio-, halogeno-, carbon-substituents, etc.), total synthesis from noncarbohydrate precursors may be easier and advantageous.” scgc.epfl.ch/load/cours\_chim/pvogel\_glycochemistry\_total\_synthesis\_of\_carbohydrates.pdf ---
**Author:** ![Halfbaker](https://avatars.discourse-cdn.com/v4/letter/h/90db22/32.png) [@Halfbaker](https://boards.straightdope.com/u/Halfbaker)\ **Post date:** [February 26, 2011, 11:39pm UTC](https://boards.straightdope.com/t/can-humans-cost-effectively-synthesize-glucose-fructose-with-solar-power/346861/4 "2011-02-26T23:39:06Z")
The technology may not be here yet, but in the long run artificial methods designed by intelligent beings are almost definitely going to overtake those that are produced accidentally through natural selection. Especially if you don’t waste energy endothermically producing O2 from CO2. Solar panels have already been produced that are more efficient than leaves for example. ---
**Author:** ![Blake](https://avatars.discourse-cdn.com/v4/letter/b/a9a28c/32.png) [@Blake](https://boards.straightdope.com/u/Blake)\ **Post date:** [February 27, 2011, 12:08am UTC](https://boards.straightdope.com/t/can-humans-cost-effectively-synthesize-glucose-fructose-with-solar-power/346861/5 "2011-02-27T00:08:22Z")
> [@Halfbaker](#): > > The technology may not be here yet, but in the long run artificial methods designed by intelligent beings are almost definitely going to overtake those that are produced accidentally through natural selection. Can we see your evidence for this claim? > [@](#): > > Especially if you don’t waste energy endothermically producing O2 from CO2. First off, in living systems O2 isn’t produced from CO2, it’s produced from H2O. Leaving that aside, what precisely do you think will happen to all the excess oxygen atoms that this reaction necessarily produces? You are starting out with 8 oxygen atoms, only 6 of them can be incorporated into your carbohydrate. So what are you going to do with the rest of them if not release them endothermically as O2 gas? Do you propose to emit ozone instead? Even if you do, how would that be energetically more favourable than the release of O2? > [@](#): > > Solar panels have already been produced that are more efficient than leaves for example. No, they are not. There are no solar panels that are capable of producing carbohydrate at all. There are solar panels that are capable of producing electricity than can be used to power other devices that produce carbohydrate. But that process is nowhere near as efficient as using leaves. ---
**Author:** ![Smeghead](https://avatars.discourse-cdn.com/v4/letter/s/f1d935/32.png) [@Smeghead](https://boards.straightdope.com/u/Smeghead)\ **Post date:** [February 27, 2011, 2:43pm UTC](https://boards.straightdope.com/t/can-humans-cost-effectively-synthesize-glucose-fructose-with-solar-power/346861/6 "2011-02-27T14:43:30Z")
> [@](#): > > Can humans cost effectively synthesize glucose & fructose with solar power Yes, we do it all the time. Vast swathes of our landscape is devoted to this practice. I’m amazed you haven’t seen it. It’s called “agriculture”. ---
**Author:** ![Wesley\_Clark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/wesley_clark/32/20581_2.png) [@Wesley\_Clark](https://boards.straightdope.com/u/Wesley_Clark)\ **Post date:** [February 27, 2011, 10:47pm UTC](https://boards.straightdope.com/t/can-humans-cost-effectively-synthesize-glucose-fructose-with-solar-power/346861/7 "2011-02-27T22:47:13Z")
> [@Smeghead](#): > > Yes, we do it all the time. Vast swathes of our landscape is devoted to this practice. I’m amazed you haven’t seen it. It’s called “agriculture”. I bow before your brilliance. But when I wrote the OP I believe I was thinking about calorie production in a post apocolyptic environment. ie, if this ‘agriculture’ you speak of no longer existed (like if a meteor hit the planet and we had to live underground), could we synthesize carbohydrates using solar power and carbon dioxide from the atmosphere in an affordable fashion. ---
**Author:** ![Exapno\_Mapcase](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/exapno_mapcase/32/1051_2.png) [@Exapno\_Mapcase](https://boards.straightdope.com/u/Exapno_Mapcase)\ **Post date:** [February 28, 2011, 12:27am UTC](https://boards.straightdope.com/t/can-humans-cost-effectively-synthesize-glucose-fructose-with-solar-power/346861/8 "2011-02-28T00:27:25Z")
> [@Wesley\_Clark](#): > > I bow before your brilliance. But when I wrote the OP I believe I was thinking about calorie production in a post apocolyptic environment. > > ie, if this ‘agriculture’ you speak of no longer existed (like if a meteor hit the planet and we had to live underground), could we synthesize carbohydrates using solar power and carbon dioxide from the atmosphere in an affordable fashion. If a meteor that big hit, the dust from the impact would blacken the sky for many human lifetimes. What solar power are you talking about? And what technology would survive? IOW, if the current answer to your question is no, how does it become yes under those circumstances? And what possible meaning could “affordable” have in such a future? ---
**Author:** ![sisu](https://avatars.discourse-cdn.com/v4/letter/s/df705f/32.png) [@sisu](https://boards.straightdope.com/u/sisu)\ **Post date:** [February 28, 2011, 12:44am UTC](https://boards.straightdope.com/t/can-humans-cost-effectively-synthesize-glucose-fructose-with-solar-power/346861/9 "2011-02-28T00:44:15Z")
> [@Halfbaker](#): > > The technology may not be here yet, but in the long run artificial methods designed by intelligent beings are almost definitely going to overtake those that are produced accidentally through natural selection. Especially if you don’t waste energy endothermically producing O2 from CO2. Solar panels have already been produced that are more efficient than leaves for example. So in effect rather than evolution we will have Intelligently Designed food? ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [February 28, 2011, 11:05am UTC](https://boards.straightdope.com/t/can-humans-cost-effectively-synthesize-glucose-fructose-with-solar-power/346861/10 "2011-02-28T11:05:34Z")
> [@sisu](#): > > So in effect rather than evolution we will have Intelligently Designed food? We already have that. ---
**Author:** ![Halfbaker](https://avatars.discourse-cdn.com/v4/letter/h/90db22/32.png) [@Halfbaker](https://boards.straightdope.com/u/Halfbaker)\ **Post date:** [May 30, 2011, 7:02am UTC](https://boards.straightdope.com/t/can-humans-cost-effectively-synthesize-glucose-fructose-with-solar-power/346861/11 "2011-05-30T07:02:33Z")
> [@](#): > > Can we see your evidence for this claim? Evolution is blind. Note I said “almost certainly” exclusively to account for unfalsifiable nature of the statement. It just seems unlikely the there isn’t at least one improvement that’s out of the the grasp of biology due to a lack of easy evolutionary pathways leading to it. No animals have wheels for example, there are just no states in between a wheel-less animal and a wheeled one that could possibly be fit. > [@](#): > > First off, in living systems O2 isn’t produced from CO2, it’s produced from H2O. > > Leaving that aside, what precisely do you think will happen to all the excess oxygen atoms that this reaction necessarily produces? You are starting out with 8 oxygen atoms, only 6 of them can be incorporated into your carbohydrate. So what are you going to do with the rest of them if not release them endothermically as O2 gas? > > Do you propose to emit ozone instead? Even if you do, how would that be energetically more favourable than the release of O2? Firsly, thank you for the correction. Actually, on the contrary, one could argue that several molecules of both CO2 & H2O are involved in the reaction that powers photosynthesis, and regardless of which one is the actual contributor of O2 on the fine scale that oxygen atoms likely can and do exchange positions throughout the reaction through quantum tunneling. Secondly, I’m not going to use “this reaction” as you put it. > [@](#): > > No, they are not. > > There are no solar panels that are capable of producing carbohydrate at all. There are solar panels that are capable of producing electricity than can be used to power other devices that produce carbohydrate. But that process is nowhere near as efficient as using leaves. The best solar panels have an efficiency of 40%. (This part cut & pasted) Only light within the wavelength range of 400 to 700 nm (photosynthetically active radiation, PAR) can be utilized by plants, effectively allowing only 45 % of total solar energy to be utilized for photosynthesis. Furthermore, fixation of one CO2 molecule during photosynthesis, necessitates a quantum requirement of ten (or more), which results in a maximum utilization of only 25% of the PAR absorbed by the photosynthetic system. On the basis of these limitations, the theoretical maximum efficiency of solar energy conversion is approximately 11%. In practice, however, the magnitude of photosynthetic efficiency observed in the field, is further decreased by factors such as poor absorption of sunlight due to its reflection, respiration requirements of photosynthesis and the need for optimal solar radiation levels. The net result being an overall photosynthetic efficiency of between 3 and 6% of total solar radiation. The process you suggest is what I refer to. As to to the efficiency problem I’ll say what I said before, the technology may not be here yet, but… ---
**Author:** ![jz78817](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jz78817/32/1028_2.png) [@jz78817](https://boards.straightdope.com/u/jz78817)\ **Post date:** [May 30, 2011, 12:46pm UTC](https://boards.straightdope.com/t/can-humans-cost-effectively-synthesize-glucose-fructose-with-solar-power/346861/12 "2011-05-30T12:46:13Z")
> [@Wesley\_Clark](#): > > I bow before your brilliance. But when I wrote the OP I believe I was thinking about calorie production in a post apocolyptic environment. > . thank you for clearing that up, 'cos when I read your OP the first thing I thought was "the last thing we need is _more sugar._