Microbes and algae as macro and micronutrient sources


#1

So after determining that official Soylent would take, at a minimum, 1/5 of a football field to grow the macro-nutrients, I started looking at different yeast, bacteria, and algae as nutrient sources.

Vitamin B-12 is the hardest to get, in my estimation, since in the normal diet, it depends on meat from ruminants that get the bacteria from food on the ground. I dug in and found that you can grow cultures of bacteria, process and centrifuge the cultures, and extract pure vitamin b-12.

For protein, I found a nice study that goes through the entire process of grinding and centrifuging crushed dry algae in pure water to extract the protein. Chlorella is an excellent source of protein.

Scenedus Dimorphus is a single celled algae that can produce up to 50% of its weight as fat.

I’m using http://www.oilgae.com/algae/comp/comp.html as a basis for algae compositions.

It seems to me that you could grow the algae, dry and crush it, and then use different processing techniques to separate the desired macro-nutrients from the rest of the biomass. The lipid profiles of algaes are generally very good.

I would grow the algae in flat vertical tanks that had growlight LEDs on each side, with the appropriate spectrum to maximize production of the relevant macro-nutrient.

This paper shows chlorella’s growth rate to be 0.6g/L day , which I interpret as .6 grams per liter per day. Assuming an 80% efficiency for extraction of protein, and a need for roughly 90 grams of protein per day, 200 Liters of algae production space is required to grow sufficient amounts. This would be .2 cubic meters (1 liter = .001 cubic meters).

This would be 2 10 cm x 1m x 1m tanks … not very big. Manipulating the water chemistry and lighting spectrum could increase yield.

For lipids, assuming the protein extraction method destroys everything not-protein, then you’d need an additional 65 grams of oils. Chlorella could again be used, and with the same growth rate, with 12% biomass being oils and 80% extraction efficiency, you’d need 65/(.8*(.14*.6)) liters , or 968L, or .968 cubic meters. You could round it up to another 10 10cm x 1m x 1m tanks - so far, 12 of these tanks are needed.

For carbohydrates, under the same formula, 250g of carbs are needed per day. Around 20% of chlorella can be carbohydrates, so 250/(.8*(.2*.6)) liters , or 2605 liters. This could be rounded up to another 27 tanks, bringing us to 39 tanks in total. All in all, we’re looking at roughly 3.9 cubic meters of space to produce the entire range of macro-nutrients, assuming the extraction methods are exclusive to the macro-nutrient being extracted, and efficiency of extraction is 80%.

If all the nutrients could be extracted sequentially, then the carbohydrates would need the most space, or 2.7 cubic meters. If you increased the extraction efficiency to 95%, then you can reduce it further to 2.4 cubic meters.

I’m going to assume a need for 25 of these tanks to produce sufficient macro-nutrients for daily consumption of 1 individual. Assuming a drying, crushing, processing, centrifuge station, nicely manufactured, could take up an additional 1.5 cubic meters, we’re given a bioreactor that’s 4 cubic meters that can produce all the macro-nutrients needed for human nutrition. This is a heck of a lot smaller than 1/5th of a football field.

The extracts would need additional processing to convert the starches into maltodextrin, and to make the protein and oils more palatable. Nonetheless, I think this avenue of research is interesting. If efficiencies and yields could be substantially improved in a controlled environment, you could reduce the entire equation of macronutrient production to a matter of the cost of electricity and fertilizer.

Here’s where my math might be completely off the reservation: With 25 of these tanks each needing the equivalent of solar input, and solar LEDs offering up roughly the same energy to the algae at a target spectrum, you’ll need roughly .6kW/H each day, per panel. If you were doing this commercially, then your electricity cost would be around 12 cents per kW/H , so each tank would cost 7.2 cents. All of them together would come out to $1.80 a day.

I’m thinking this is probably off by an order of magnitude and that the actual cost would be 18 cents per day. I’ll look into correcting this.


#2

That’s really impressive calculations you are doing there, but practically speaking at least on the market algae-derived protein is actually very expensive. I couldn’t tell you why, maybe it’s just not mass produced or just sold at ridiculous markups?

I’m guessing you aren’t factoring in efficiency benefits of GMOs or artificial selection (which close to 100% of human crops and livestock have been subject to, but algae probably not)? That’s one way to tackle the problem.


#3

Yields can be improved, the issue is that said fertilizer can be very costly. Obviously the fertilizer in question would vary based on organism used in this scenario. Also light levels may affect growth as well, the paper you linked to growth rate seemed to be based on thermal variance.

As @joemoe said, GMOs can provide different efficiencies, and in some cases, can be tweaked to export the desired materials into the surrounding water, meaning you’d just have to cycle the water. There are probably many methods to get the desired materials out of your favorite producer.

I think the biggest issue is where is it getting the nutrients it needs to make the products we desire. I mean, its not magic, it can’t make something out of nothing. Most plants have roots to obtain what they need, you’d have to constantly check the water to make sure it has whats needed to make the desired end products. The fertilizer may be the most expensive part, but when estimating cost, its always best to guess higher and be conservative with your estimates.


#4

There would have to be bubblers to keep the correct level of CO2, fertilizer input to keep the water chemistry right, and provide the nutrients the algae needs, and so on. GMO and altered growing conditions (heat, nutrition, light, light frequency) could drastically alter the macronutrient balance, I’m sure - you could probably get 60% of weight as carbs, protein, or oil, individually.

You could also, presumably, breed for desired traits, like any other organism. Making the cell walls more fragile would increase yield and reduce processing requirements. The waste from processing could conceivably be used to augment the fertilizer, and so on. If you could increase the size of the organisms (that’d be a fun experiment - breeding super-sized chlorella by separating larger organisms for selective breeding) that would also increase efficiency.

I tried to estimate conservatively with this initial guesstimate. I’ll need to do more research.

In the meantime, here’s a neat website: http://www.algaedepot.org/


#5

This is awesome. Thanks for sharing your deep-dive in such detail so the rest of us can benefit from your research.


#6

Using ammonium sulfate and water, you can precipitate protein. Filtering out the precipitate and “washing” it with water removes the ammonium sulfate, and eventually results in high purity protein isolate.

I see the process going like this: Algae is grown, filtered, then dried. The dry algae is crushed (pressed between steel rollers multiple times) and then mixed into an alcohol solution. This separates the oil from the carbohydrate / protein / cellulose biomass. The mixture is stirred (for some amount of time until the separation is complete) and then dried again. The biomass is then added to pure water, stirred/agitated, and the oil is skimmed. Ammonium sulfate is added, causing the protein to precipitate, and then after the desired level of precipitation, filtered out. The filtered protein is then dried, crushed, and washed through multiple cycles, until no ammonium sulfate is left in the isolated protein.

The leftover biomass from the protein precipitation contains the starches (carbs) and cellulose. I’m still working out how the starches should be processed.

My earlier post referred to centrifuging the crushed algae, which is energy intensive. These processes are chemical, rather than mechanical. I’ll eventually go full circle and figure out how to obtain ammonium sulfate and ethanol from the process to make it as sustainable as possible.

The reason for processing the algae, rather than crushing and consuming it whole, is to have control over the micronutrients. The mineral contents can be toxic, so separating the macro nutrients from the micro is desirable. Once this is done, the micronutrients can be added back in, in the appropriate proportions.

I have no idea what the vitamin profiles of the isolated protein and oils look like, but I’m willing to bet they’re very low.

Yeast protein can be isolated in the same way. I was thinking that since ethanol is needed, then a yeast bioreactor could be made to use the cellulose and carbohydrate biomass leftover after the protein and oil extraction.

Separating the carbohydrates seems difficult, since they’re stuck in the biomass containing the chlorophyll, cellulose, and other leftovers. This might be possible by mixing it into an alcohol solution, which should dissolve the carbohydrates, and after separating the undissolved portion, what’s left after drying the solution should be pure carbohydrates - algae starch.

Low energy chemistry is a lot more efficient than high energy mechanical centrifuge. :wink:

Producing a nice distillable alcohol from the process would be an unexpected benefit.


#7

I’m not quite sure what this is referring to, but I am tired so it may come to me later… but for those anti-chemical names people who may read this: Ammonium Sulfate is GRAS (generally regarded as safe), and if you think ethanol is dangerous, stop drinking your beer, vodka, whiskey, etc.

Few issues/questions with the chemical method. First is, what is its re usability? Surely you cant get all of your ammonium sulfate back in the separation process. Second, how does one remove the salts from the proteins, is it reusable, and is it GRAS? Third, is there a limit to the precipitation amount, or does it precipitate it all out over time?

Does cellulose behave differently than the other carbohydrates? It is technically a polysaccharide, though it does tend to be quite large, so it could be the size causes it to behave differently in an alcohol solution.

Any ideas on the rate the yeast would make alcohol from the cellulose, and how much cellulose you would set aside as dietary fiber? ( on dietary fiber http://en.wikipedia.org/wiki/Dietary_fiber#Types_and_sources_of_dietary_fiber )


#8

Depends on the micronutrients.

I will be getting a house in August or September and dedicating a room as a lab - I want to set up a bioreactor with LED grow lights. I’ll start producing algae and processing it into purified macros, and then determine the chemical composition of the isolates. Once I’ve got the chemical composition down, I can determine how much of the cellulose to use for fiber, and so on.

The goal would be a machine that you plug in, and it produces a complete-nutrition meal.


#9

What would the amino acid profile of the algae-produced protein be? My biggest fear with some of these other protein sources is that they’ll be missing some of the key amino acids that the human body won’t produce.


#10

The algae I linked to has a complete amino acid profile - and many of them do. They’re great food sources, if you can separate them from the micronutrients that might otherwise cause overages (things like iron, and so forth.) I’ve been looking into whether algae growth with restricted nutrient intake can still produce equivalent nutritional benefits. For example, if you provide no iron in the algae’s nutrient mix, it’s not going to spontaneously produce iron. So if you were to specifically restrict the nutrient intake to algae so that it contained only the desired proportions, then you could theoretically have many of the minerals apportioned out of the box, as it were. Other vitamins may be subject to similar methods, by subjecting the organism to different lighting, temperature and chemical environmental changes.

Aside from vitamin B, I’m betting that multiple strains of algae (or cyanobacteria) could be produced that provided specific nutritional profiles, despite the generic nutrient composition of an organism. The organisms will adapt to their environment, and those adaptations can be predicted and leveraged.