Author Topic: Algae for space food  (Read 34127 times)

Offline DarkenedOne

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Algae for space food
« on: 10/06/2011 09:34 pm »
There has been a great deal of talk about these 2nd generation bio fuels especially biodisesl from algae, and I was thinking about how spaceflight could really use them.

It seems to me that these algae technologies could be used to provide both nutriution and oxygen for human spaceflight.  The algae fuel systems consume CO2, water, and sunlight to produce oxygen and simple sugars, like all plants do.  However unlike the plants that we normally eat, they do not require all the various minerials and conditions that are required for more complex lifeforms.  They also have growing times on the order of a few days, which is very fast  compared to plants.     

What I have been thinking is that long duration human spacecraft could use a simple pipes on the outside of the spacecraft as a bio reactor.  The pipes would be exposed to the sunlight, and will use filters and shutters to filter out radiation that is harmful for the algae.  CO2 would be extracted from the crew area, concentrated, and pumped into the bio reactor.  The algae would then consume the CO2 and release O2, which would be pumped back into the crew cabin.  Of course new food processing techniques would have to be developed to transfer the sugar filled algae into something edible. 

If you think about it algae, as well as, other simple organisms are ideal for space food production, because unlike the more complex lifeforms that we recieve most of our food from they require little in resources, and have very quick growth times.  Since they are simple they can also be easily genetically engineered to produce the things we need from sunlight.

Offline gbaikie

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Re: Algae for space food
« Reply #1 on: 10/07/2011 03:07 am »
There has been a great deal of talk about these 2nd generation bio fuels especially biodisesl from algae, and I was thinking about how spaceflight could really use them.

It seems to me that these algae technologies could be used to provide both nutriution and oxygen for human spaceflight.  The algae fuel systems consume CO2, water, and sunlight to produce oxygen and simple sugars, like all plants do.  However unlike the plants that we normally eat, they do not require all the various minerials and conditions that are required for more complex lifeforms.  They also have growing times on the order of a few days, which is very fast  compared to plants.     

What I have been thinking is that long duration human spacecraft could use a simple pipes on the outside of the spacecraft as a bio reactor.  The pipes would be exposed to the sunlight, and will use filters and shutters to filter out radiation that is harmful for the algae.  CO2 would be extracted from the crew area, concentrated, and pumped into the bio reactor.  The algae would then consume the CO2 and release O2, which would be pumped back into the crew cabin.  Of course new food processing techniques would have to be developed to transfer the sugar filled algae into something edible. 

If you think about it algae, as well as, other simple organisms are ideal for space food production, because unlike the more complex lifeforms that we receive most of our food from they require little in resources, and have very quick growth times.  Since they are simple they can also be easily genetically engineered to produce the things we need from sunlight.

Do not know how you extract CO2 from air.
Activated carbon and recycle the activated carbon?
Other than chemical processes [such as making methane for example]
not sure how you get this impurity out of the air- 1000 ppm is .1 % and might might want to try to get down to level of 1000 ppm.

One could mix the water with the air- use cold and pressurized water- maybe?
A problem is no gravity.

Edit: I think growing some thing like lettuce and tomatoes could be easier. And lots herbs: clives, Watercress, mint, etc.
« Last Edit: 10/07/2011 07:02 pm by gbaikie »

Online mmeijeri

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Re: Algae for space food
« Reply #2 on: 10/07/2011 03:20 am »
Algae have been studied for bioregenerative life support, notably in ESA's Melissa project. Spirulina turns out to be one of the best candidates. It is chock-full of everything you need, including vitamins.

There's a big snag though, humans cannot eat more than ~100g/day of algae (or more generally single cell protein) without getting gout. Somewhere during our evolution we lost the ability to break down uric acid, which is a product of DNA / RNA digestion and when we get too much of it, it forms the painful crystals responsible for gout. Spirulina is an excellent food supplement, but not suitable as the main component of your diet. Plus you don't want to be eating nothing but algae soup every day.

Fish on the other hand do have the ability to break down uric acid, and Tilapia thrive on a Spirulina diet, so the combination would be very useful for human consumption.
« Last Edit: 10/07/2011 08:29 pm by mmeijeri »
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Offline JohnFornaro

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Re: Algae for space food
« Reply #3 on: 10/07/2011 01:01 pm »
Hah.  Beat me to the Sirulina food supplement observation.  Algae (algea?  I should look this up.)  is a great enabler of aquaculture.  Aquaculture could certainly help with the food supply and atmo refreshment on a lunar base.  I wonder if there could be an aquarium experiment on ISS to fiddle around with the idea; the experiment should take place in a one sixth gee centrifuge, however.
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Offline IsaacKuo

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Re: Algae for space food
« Reply #4 on: 10/07/2011 02:56 pm »
Aquaculture is a wonderful idea if you can afford the mass budget of all the water.  For example, if your mission requires long term high energy GCR shielding, then you might require 5 tons per square meter of water anyway.

But if you need to conserve mass, aeroponics seem to be a more promising direction.  Besides minimizing water mass, aeroponics also minimizes disease spread.

Offline strangequark

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Re: Algae for space food
« Reply #5 on: 10/07/2011 03:24 pm »
There's a big snag though, humans cannot eat more than ~100g/day of algae (or more generally single cell proteine) without getting gout. Somewhere during our evolution we lost the ability to break down uric acid, which is a product of DNA / RNA digestion and when we get too much of it, it forms the painful crystals responsible for gout. Spirulina is an excellent food supplement, but not suitable as the main component of your diet. Plus you don't want to be eating nothing but algae soup every day.

Fish on the other hand do have the ability to break down uric acid, and Tilapia thrive on a Spirulina diet, so the combination would be very useful for human consumption.

You'd think it wouldn't be that hard to remove the uric acid component, though.

Online mmeijeri

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Re: Algae for space food
« Reply #6 on: 10/07/2011 03:29 pm »
You'd think it wouldn't be that hard to remove the uric acid component, though.

The uric acid is produced by the human body as it breaks down the RNA/DNA from the algae, so you'd have to somehow break down the uric acid inside the human bloodstream, or to break down the food before eating it as they presumably do for intravenous feeding. I've read there is an experimental drug that can help the body break down uric acid, but I think it has nasty side effects.

And of course, that still doesn't solve the algae soup all day, every day problem.
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Offline DarkenedOne

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Re: Algae for space food
« Reply #7 on: 10/07/2011 04:14 pm »
Do not know how you extract CO2 from air.
Activated carbon and recycle the activated carbon?
Other than chemical processes [such as making methane for example]
not sure how you get this impurity out of the air- 1000 ppm is .1 % and might might want to tried to get down to level of 1000 ppm.

One could mix the water with the air- use cold and pressurized water- maybe?
A problem is no gravity.

Edit: I think growing some thing like lettuce and tomatoes could be easier. And lots herbs: clives, Watercress, mint, etc.

First of all, pure CO2 is not a requirement.  Algae in its natural environment works fine with CO2 in the concentration it exists in our atmosphere just like plants.

Second of all, CO2 can be concentrated using filters, and a variety of other methods.

Lastly concentrating the CO2 is desirable because it allows the algae to grow faster due the greater access its raw material, carbon.

Like I stated before the problem with lettuce, tomatoes, as well as other more complex forms of life is that they have grow slower, require more minerals, and are more sensitive to their environment, thus they require more resources.
« Last Edit: 10/07/2011 04:17 pm by DarkenedOne »

Offline DarkenedOne

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Re: Algae for space food
« Reply #8 on: 10/07/2011 04:20 pm »
Algae have been studied for bioregenerative life support, notably in ESA's Melissa project. Spirulina turns out to be one of the best candidates. It is chock-full of everything you need, including vitamins.

There's a big snag though, humans cannot eat more than ~100g/day of algae (or more generally single cell proteine) without getting gout. Somewhere during our evolution we lost the ability to break down uric acid, which is a product of DNA / RNA digestion and when we get too much of it, it forms the painful crystals responsible for gout. Spirulina is an excellent food supplement, but not suitable as the main component of your diet. Plus you don't want to be eating nothing but algae soup every day.

Fish on the other hand do have the ability to break down uric acid, and Tilapia thrive on a Spirulina diet, so the combination would be very useful for human consumption.

Well that is what I was talking about when I mentioned food processing.  I was imagining that algae would not be terribly tasty. 

The raw material is there we just need to do food processing to turn it into something useful.

Offline DarkenedOne

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Re: Algae for space food
« Reply #9 on: 10/07/2011 04:27 pm »
Aquaculture is a wonderful idea if you can afford the mass budget of all the water.  For example, if your mission requires long term high energy GCR shielding, then you might require 5 tons per square meter of water anyway.

But if you need to conserve mass, aeroponics seem to be a more promising direction.  Besides minimizing water mass, aeroponics also minimizes disease spread.

All the water would be recycled. 

The algae take CO2, the H2O, and sunlight for energy, and transforms it into various organic molecules and O2.  The astronauts do the reverse by consuming the organic molecules with O2, and emit CO2, and water.  It is  a small ecosystem.

Aeroponics requires far more resources due to slow growth times, and lower concentrations of raw materials.


Offline RanulfC

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Re: Algae for space food
« Reply #10 on: 10/07/2011 05:21 pm »
Should probably inject that Algea is also usable for things like phytomining (sp? 'cause it "looks" right :) ) and soil contamination mitigation which it's used for here on Earth.

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Offline IsaacKuo

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Re: Algae for space food
« Reply #11 on: 10/07/2011 06:34 pm »
Aquaculture is a wonderful idea if you can afford the mass budget of all the water.  For example, if your mission requires long term high energy GCR shielding, then you might require 5 tons per square meter of water anyway.

But if you need to conserve mass, aeroponics seem to be a more promising direction.  Besides minimizing water mass, aeroponics also minimizes disease spread.

All the water would be recycled.

That's not the issue.  The issue is that algae require a lot of water to live because they must be immersed in water.  Aeroponic plants do not need to be immersed in water.  Instead, they are immersed in air, which has a far lower density than water.

Quote
Aeroponics requires far more resources due to slow growth times, and lower concentrations of raw materials.

In fact, the high productivity of aeroponics for a given system mass is the reason why NASA has devoted so much research into aeroponics (as opposed to aquaculture or hydroponics).

Aeroponics have high productivity for various reasons, including the fact that they are immersed in air rather than water.  This provides optimal availability of CO2 and oxygen to the root system.

Note that if you're using tilapia for food rather than directly using the algae for food, you cut your effective productivity by an order of magnitude.  Each layer of a food chain is roughly an order of magnitude cut in efficiency.  In contrast, aeroponic crops can be used directly for the entire diet--including complete proteins from a variety of legumes.

Offline gbaikie

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Re: Algae for space food
« Reply #12 on: 10/07/2011 07:36 pm »
Do not know how you extract CO2 from air.
Activated carbon and recycle the activated carbon?
Other than chemical processes [such as making methane for example]
not sure how you get this impurity out of the air- 1000 ppm is .1 % and might might want to tried to get down to level of 1000 ppm.

One could mix the water with the air- use cold and pressurized water- maybe?
A problem is no gravity.

Edit: I think growing some thing like lettuce and tomatoes could be easier. And lots herbs: clives, Watercress, mint, etc.

First of all, pure CO2 is not a requirement.  Algae in its natural environment works fine with CO2 in the concentration it exists in our atmosphere just like plants.

Second of all, CO2 can be concentrated using filters, and a variety of other methods.

Lastly concentrating the CO2 is desirable because it allows the algae to grow faster due the greater access its raw material, carbon.

Like I stated before the problem with lettuce, tomatoes, as well as other more complex forms of life is that they have grow slower, require more minerals, and are more sensitive to their environment, thus they require more resources.


The only filter I know that takes CO2 out of the air is a carbon activated filter. A carbon activated filter is good for taking any impurity out of the air. But these filters wear out and need to be replaced with fresh carbon activated filters. That's not a big problem bring lots of fresh filters- but getting the carbon dioxide captured from the air with these filter to the algae in the water is the part I don't know how one could do.

We could skip the use of any other kind removable CO2 from the air if one could mix crew air with water of algae- just not sure what best way to do this in zero gee. In gravity you simply pump the air into the water- something similar those bubbly things in a fish tank. Perhaps one turn water into a mist- like garden hose. Do in a box and water will clump to together and you pump out the liquid water [enriched with CO2 of crew air]. If this is cold the crew air would not return to crew with much humidity and water will mix well with CO2.

Edit: And/or simply remove humidity from crew air, and put that water in the algae water.
« Last Edit: 10/07/2011 07:45 pm by gbaikie »

Online mmeijeri

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Re: Algae for space food
« Reply #13 on: 10/07/2011 07:45 pm »
Like I stated before the problem with lettuce, tomatoes, as well as other more complex forms of life is that they have grow slower, require more minerals, and are more sensitive to their environment, thus they require more resources.

On the up side, they also enhance the subjective quality of the food considerably. There are plans for some sort of a "salad bar" on the ISS with home grown lettuce etc.
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Offline IsaacKuo

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Re: Algae for space food
« Reply #14 on: 10/07/2011 07:54 pm »
... if one could mix crew air with water of algae- just not sure what best way to do this in zero gee. In gravity you simply pump the air into the water- something similar those bubbly things in a fish tank.

This will work for aquaculture.  Your aquaculture "bioreactor" is fundamentally a closed loop water pipe which you pump using one or more pumps.  For simplicity, let's say there's just one centrifugal pump.  You can introduce air bubbles around the outer rim of the pump, and the bubbles will flow inward to the center.  Along the centerline is a region of air from which you output "exhaust" air back into the main environment.  This "exhaust" air picks up some oxygen that was generated by the algae.

Offline beb

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Re: Algae for space food
« Reply #15 on: 10/07/2011 07:57 pm »
The only filter I know that takes CO2 out of the air is a carbon activated filter. A carbon activated filter is good for taking any impurity out of the air. But these filters wear out and need to be replaced with fresh carbon activated filters. That's not a big problem bring lots of fresh filters- but getting the carbon dioxide captured from the air with these filter to the algae in the water is the part I don't know how one could do.

We could skip the use of any other kind removable CO2 from the air if one could mix crew air with water of algae- just not sure what best way to do this in zero gee. In gravity you simply pump the air into the water- something similar those bubbly things in a fish tank. Perhaps one turn water into a mist- like garden hose. Do in a box and water will clump to together and you pump out the liquid water [enriched with CO2 of crew air]. If this is cold the crew air would not return to crew with much humidity and water will mix well with CO2.

Edit: And/or simply remove humidity from crew air, and put that water in the algae water.

Not that I like this idea at all but, carbon dioxide readily condenses with refrigeration and pressure so extracting it from the cabin air would not be a problem. The CO2, warmed back into a gas could be injected into a column of tank water slowly being pushed through a coil by a pump. The coil is to give it sufficient contact time for the CO2 to dissolve into the water. At the end of the coil the water enters a centrifuge where the water separates from the gases.  That part is easy. Extracting the algae from the water.... that's the hard part. Too much water, too little algae. That way biofuels from algae hasn't gotten anywhere. Too hard to concentrate the algae.

Online mmeijeri

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Re: Algae for space food
« Reply #16 on: 10/07/2011 07:58 pm »
Note that if you're using tilapia for food rather than directly using the algae for food, you cut your effective productivity by an order of magnitude.  Each layer of a food chain is roughly an order of magnitude cut in efficiency.  In contrast, aeroponic crops can be used directly for the entire diet--including complete proteins from a variety of legumes.

That's a very important point. Mussels and various other clams could perhaps be cheaper than fish, while shrimp and possibly lobsters should also be possible. One very interesting possibility is insects. Doesn't sound too appealing to western ears, but entomophagy is common in many parts of the world, precisely because it requires fewer scarce resources. It would likely be more expensive than legumes, but less expensive than fish, which in turn is much less expensive than meat. Mushrooms are also a good choice. You'd end up with some kind of pescetarian diet minus dairy products, eggs and perhaps honey, without fruits like bananas, apples, pears etc, but with garden strawberries and perhaps some other small fruits. Plus the aforementioned insects. Whenever I read articles about this sort of stuff I feel like having a snack... Except for the insects.
« Last Edit: 10/07/2011 08:33 pm by mmeijeri »
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Offline IsaacKuo

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Re: Algae for space food
« Reply #17 on: 10/07/2011 08:16 pm »
It occurs to me that your pump could actually be powered by airflow.  That way you don't have any submerged vanes or anything that could get clogged up by algae.  The main centrifugal pump is a cylinder, with water input near the center and water output near the edge.

Around the edges are several air injector pipes, which inject high speed high pressure air parallel to the edge.  This imparts spin to the water and air.  Due to the spin, the air migrates inward to the center, while the water migrates outward to the edge.  The air exchaust is at the center, which is where oxygenated air returns to the main habitat.

Remember folks, transfer of CO2 to the water is only half the problem--transfer of O2 to the air is the other half.  Fortunately, nature is fine with solving both problems with simply mixing.

Offline Robotbeat

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Re: Algae for space food
« Reply #18 on: 10/07/2011 09:11 pm »
You'd think it wouldn't be that hard to remove the uric acid component, though.

The uric acid is produced by the human body as it breaks down the RNA/DNA from the algae, so you'd have to somehow break down the uric acid inside the human bloodstream, or to break down the food before eating it as they presumably do for intravenous feeding. I've read there is an experimental drug that can help the body break down uric acid, but I think it has nasty side effects.

And of course, that still doesn't solve the algae soup all day, every day problem.
I really think that specialized drugs like that are going to be the key to future off-world colonization techniques (not being injected daily, but administered slowly via artificial organs... just glorified plastic dealies with semi-permeable membranes that slowly release drugs... or perhaps just taken daily in pill form). If a pill is all it takes for us to eat low enough on the food chain that producing food off-world becomes practical, then that's probably what we'll do. That's relatively far-future, though.

I expect that concentrated, non-perishable food (supplemented with things easily grown on board a spacecraft, like lettuce, herbs, and maybe tomatoes) will be the norm for human spaceflight for most of this century. How many calories can you fit into a pound of food? If it's all fat, then 4000 Calories. If it's all protein or carbohydrates, then a little more than half that. Fat should only be up to 35% your calories (and you only need about 25 grams of micronutrients a day, 38 grams of fiber--which will be insoluble to avoid problems with gas ;) ), so the rest is a mix of carbs and proteins (mostly carbs).

If fat is 9 kcal/gram, and proteins and carbs are 4 kcal/gram, and you need 2500kcal per day, then we're looking at: .35*2500kcal/(9kcal/gram)+.25*2500kcal/(4kcal/gram)+.4*2500kcal/(4kcal/gram)+25grams+38grams = 566.5 grams per day of concentrated food, plus water (which can be recycled and isn't counted here).
This is for an adult male on a 2500kcal diet. Female adults would need approximately 20% less (2000kcal diet), thus ~453 grams of concentrated food.
If you had a mix of male and female astronauts, that comes pretty close to .5 kg of concentrated food a day, plus packaging and water.
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Offline IsaacKuo

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Re: Algae for space food
« Reply #19 on: 10/07/2011 09:33 pm »
Lettuce, herbs, and tomatos have low caloric content.  Various legumes offer good caloric content, in the form of a good balance of carbohydrates and complete proteins.  They offer a wide variety of culinary possibilities, from raw/roasted/boiled peanuts and edamame to refried beans to hummus to various masalas to peanut butter.

Add in aeroponic potatos, rice, or wheat and you've got the basis for an tasty healthy diet.  (Corn is also a good food with a lot of flexibility, but it's a bit less trivial to properly process than the other staple starches.)

As for the culinary possibilities of algae--there is actually a good range of tasty possibilities, at least if you're into Japanese food.  Wakame and nori are pretty good straight, even if they're more typically eaten with other ingredients.

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