When I was in graduate school at Texas A&M in the early 90’s, I selected chemical engineering Professor Mark Holtzapple as my research advisor. His work was exactly in my area of interest: Biofuels from cellulose. Even then, I was very concerned about the non-sustainable lifestyle we were living, and I was hoping to save the world. For a very good overview on what we were doing, see this PowerPoint presentation or this article. In brief, what we were doing was searching for naturally occurring biological systems that convert cellulose to organic chemicals.
The primary system we studied was the bovine digestive system. Cattle are very efficient digesters of cellulose. They eat grass, and break it down via microorganisms that live in their digestive systems. So what we did was extract those microorganisms and attempt to convert cellulose in reactors that emulated the chemistry of the cow’s stomach. And while we did have success, the conversion was never as efficient as it was inside the cow.
So, I spent time brainstorming other efficient cellulose digesters. It occurred to me that probably the most efficient digester of cellulose in the world is the termite. After all, even cattle can’t break down wood. So I discussed it with Professor Holtzapple, and he thought it was a great idea. I searched the literature, and as far as I could determine, nobody had ever done it before. Therefore, I had no guidance at all with what I was attempting.
I arranged a meeting with a termite expert in Texas A&M’s Entomology Department. He was very keen on the idea, so he supplied the termites. The next bit was tricky. The cellulose digesters that we were looking at were anaerobic microorganisms. Oxygen would kill them. Therefore we always had to take great care to get them into the reaction system without killing them. For the cows, it was easy. We filled up a bottle with nitrogen, stuck our arm inside a portal into the stomach of a fistulated steer, extracted about a liter of stomach contents, and poured it into the nitrogen-filled bottle. We then transferred the contents to reactors that were being purged with nitrogen.
But with termites, it wasn’t going to be quite so easy. The volume of material I would be extracting would be very small, and therefore it would be tough to extract it without exposing it to air (with the equipment I had to work with). The other problem I had was that there was virtually no information available on the chemistry of the termite gut. How was I going to know what kind of vitamins, salts, etc. to put in the reactor? What should the pH be? The final concern I had was that I didn’t know exactly what the product of the reaction would be. I wanted a reaction system that would convert the cellulose to acetic acid or ethanol, and not all the way to carbon dioxide. But I really had no idea what I would get.
So, what I did was use the same reactor conditions I used for the bovine microorganisms, and I threw in a combination of live termites, termites with their hindguts opened up, and just some extracts from the hindgut. I figured that I had a pretty good chance, given this approach, to have some of those desirable microbes survive the transfer. I then let that combination ferment in the reactor for about a week.
When I tested the contents of the reactor, I was disappointed. I was after acetic acid to turn into ethanol, but what I got was butyric acid (which can be turned into butanol). But I wasn’t interested in butanol, and the amounts I got were very small. Since I was nearly at the end of my research, and I didn’t really have the facilities nor the time to figure out the termite hindgut chemistry (the real critical piece, in my mind), I abandoned my termite investigation. I still thought it was an excellent idea, and if someone had 3 or 4 years it would have made a great Ph.D. research project. But I had to move on and graduate.
Since that time, I have seen the idea come up on a few occasions. Because of my previous attempt, news of these attempts always catches my attention. Last week, I saw a new story on this:
Fuel’s gold: Termites point way to new dawn of bio-energy
Here is an extensive excerpt, describing this latest line of investigation:
PARIS (AFP) – A team of US scientists poring over the intestines of a tropical termite have a gut feeling that a breakthrough in the quest for cleaner, renewable petrol is in store.
Tucked in the termite’s nether regions, they say, is a treasure trove of enzymes that could make next-generation biofuels, replacing fossil fuels that are dirty, pricey or laden with geopolitical risk.
Termites are typically a curse, inflicting billions of dollars in pest control and termite control damage each year by munching through household timber with silent, relentless ease. But gene researchers say the hind gut of a species of Central American termite “harbour a potential gold mine” of microbes which exude enzymes to smoothly break down woody fibres and provide the insect with its nutrition.
Next-generation biofuels would use non-food cellulose materials, such as wood chips and straw. But these novel processes, hampered by costs and complications, are struggling to reach a commercial scale.
The termite’s tummy, though, could make all the difference. Like cows, termites have a series of intestinal compartments that each nurture a distinct community of microbes.
Each compartment does a different job in the process to convert woody polymers into the kind of sugars that can then be fermented into biofuel. The US team has now sequenced and analyzed the genetic code of some of these microbes in a key step towards — hopefully — reproducing the termite’s miniature bioreactor on an industrial scale.
Their work, published on Wednesday in Nature, required scientists to venture into the rainforests of Costa Rica, where they plucked bulbous-headed worker termites from a large nest at the foot of a tree.
Using fine forceps and needles, they extracted the contents of the third paunch, or hind gut, from 165 termites, and sent this to a lab in California for sequencing.
From this, some 71 million “letters” of genetic code emerged, pointing to two major bacterial lineages called fibrobacters, which degrade cellulose, and treponemes, which convert the result to fermentable sugars. Termite guts are incredibly efficient, said Andreas Brune of the Max Planck Institute for Terrestrial Microbiology in Marburg, Germany.
“In theory, they could transform an A4-sized sheet of paper into two liters (1.8 pints) of hydrogen,” he said.
To be sure, they are well beyond what I was attempting to do. They are sequencing genes, using an entirely different species of termite, and they are attempting to produce hydrogen. But the core concept is the same: Scale up the internal bioreactor of the termite to produce a desirable end-product.
I guess I was just ahead of my time. 🙂
This sounds interesting, but how much can it help? Heck, the industrial revolution denuded large parts Europe/England way back when the entire (tiny) economy was fired by wood and charcoal.
But let’s forget history and try again.
Wood, if you burn it directly, has between 12MBtu to 32.9 MBtu per cord. The 12 is cedar, the 33 is Osage Orange. Hickory (depending on the flavor) is 26.7 to 27.7. Oak is 25.7, cherry is 20, and firs and pines are 14 or 15. For fun, let’s pick 20MBtu for “wood.” If you don’t like that pick, please rework the math with your favorite flavor of wood…but please also adjust the cords/acre value. Something tells me the fast-growers have few BTU and the slow growers have a lot.
I’m going to assume that the energy conversion from wood to ashes is equivalent to what you can get going wood – intermediate chemical (e.g., ethanol) then to burned up intermediate ethanol. Is that perfectly accurate? I dunno, ask a chemist. I’d hazard a guess based on the law of conservation of energy that I’m being generous.
I’m also going to pretend that the energy conversions are “free,” that is 20MBtu of wood is 20MBtu in your gas tank or electrical generation facility…and do the same for oil. I’m *really* sure that’s being generous to wood.
BTW, the weight of a cord of wood is between 4,800 lbs to just over a ton depending on moisture and variety. Assuming dry wood, the Btu content is roughly proportional to the weight (my eyeball says about 10MBtu = 1500 lbs).
It seems that you can harvest (again, depending on the flavor of wood) 1/3 to 1 or more cord per year per acre. Let’s just say ½ for the hell of it — we got a middle wood that grows a middle speed.
Now, I’m going to ignore transportation and “harvesting” costs. Something tells me that transporting four bbl of oil (a bit over 23M Btus, just over a thousand pounds of weight, flows through pipes) is a heck of a lot easier than transporting a cord of wood (20M Btus, three thousand pounds dry, does not flow through pipes). Tar sands are expensive to “harvest,” Saudi oil isn’t, but all trees are.
All that said, here’s a back of the envelope calculation:
0.5 cords per acre*
2.00E+07 Btu per cord
1.00E+07 Btu per year per acre
2.10E+07 USA is about 21M bbl oil per day
7.67E+09 USA bbl oil per year
4.45E+16 USA Btu oil per year
4.45E+09 acres wood needed to replace oil
6.95E+06 sq miles of wood needed to replace oil
126 number of Iowas** (at 55k sq miles/Iowa)
*I saw b/w 1/3 and 2 cords/acre. 1/2 seemed to be the most common. Maybe w/ good farming, we can get 1 cord per acre of mid-grade wood, so maybe we only need 63 Iowas.
**I picked Iowa because it just seems to be one standard unit of midwestern state to me. It also is ranked about in the middle in state size. I’ve had easterners tell me that Pennsylvania is a big state. I laugh. It is only 46k square miles (#33 on the list). The entire USA is about 3.5M square miles.
Bottom line: I don’t see how this is any different than corn ethanol. We’re orders of magnitude out of the ballpark.
references for wood data:
http://www.forestry.iastate.edu/forest_products/fuel.html
http://www.forestry.iastate.edu/publications/F-370.pdf
These two range from 2 cords/acre to 1/3 cord per acre.
“On an average site in New York State, about 5 (full) cords of wood will be removed from each acre every 10 years, an average of 1/2-cord/acre/year.” (http://www.geocities.com/cicada_ridge/forest/susyield.htm citing a Cornell publication)
Another ½ cord/acre claim
http://pods.dasnr.okstate.edu/docushare/dsweb/Get/Document-2508/NREM-9439web.pdf
And another ½ cord/acre:
http://www.ces.ncsu.edu/nreos/forest/woodland/won-14.html
please feel free to check and correct my numbers and calcs.
From what I’ve read:
1. Termites can digest other plants.
2. The source to fuel the termite enzyme reaction is likely to be something which grows much faster than trees. The most common example is switchgrass, but I believe that many other plants have been suggested (such as sorgum and varieties of bamboo) These plants are both cheaper to grow, and grow much faster.
Switchgrass aficionados throw around 10 ton/acre numbers, which at 15 mmBTU/ton comes out to 1.5e08 BTU/acre. That’s 15x your number, so we only need 8 Iowas (a slice of the plains states plus part of Texas).
A recent ORNL study came up with a 1.3 billion tons of available biomass, mostly from ag and forest waste. That’s 2.0e16 BTU, almost half of your oil BTU number. I agree biomass isn’t a total replacement and maybe not even a good partial replacement for oil, but I don’t agree the potential resource is “orders of magnitude” too small. At least not for the US. Europe, Japan, etc. are obviously different stories.
==A recent ORNL study came up with a 1.3 billion tons of available biomass==
Yeah, the Perlack 2005 study.
Mostly bullshit.
http://venturebeat.com/2006/11/05/why-cellulosic-ethanol-will-not-save-us
Another interesting study came up with this graphic:
http://greyfalcon.net/biolimits.png
Developing the technology is fine, and could provide one more means of keeping us from freezing in the dark. But, in addition to problems noted here by previous posters, there will in the future be competition for inputs with food-growers. I hate to sound like a broken record, but the food-or-fuel debate is only going to intensify as time passes.
I think advocates should forget about building large-scale commercial plants, and concentrate on developing small “digesters” that could be used locally by people to produce fuel for their own needs. Locally, people will know how much organic material they can spare. Biofuel plant operators carrying off whole truckloads of organic material will create strife.
What a fascinating post by RR. Another reason why I think there is, and will be, no energy crisis. We have venture capital firms, we have free enterprise (and no, I am not a right-wing wacko. But I admire what works, and smart people who work).
Maybe we cannot grow enough wood, or biomass, to satisfy our needs entirely. But many plants grow rapidly, and do not need farmland (although, if we go to PHEVs, the best tactic mau be to farm the fastest-growing plants we can find, then burn them to turn steam engines, and power the grid. There you go, cellulosics at work.
And remember: the price signal is sending BTU per capita demand down.
Better lighting systems are available now. Higher MPG cars can be built now.
The oil problem is a tricky one. But we have solutions.
What is the point of bio-processing wood (or anything else for that matter) into ethanol, which is a difficult fuel to handle and store, when it could be cooked into syn-gas and turned into something like regular gasoline and diesel?
when it could be cooked into syn-gas and turned into something like regular gasoline and diesel?
Because you give up about 1/3 of the energy in the syngas step. Overall efficiency is something like 50-60% by the time you turn the biomass into useable products.
Biological processes are slow, but efficient. But they create aquous solutions which don’t make very good fuels, requiring distillation or other purification.
Thermal processes are fast but not thermally efficient.
The more I look at the problem, the more I believe that some kind of plug hybrid vehicle is the answer. Use off-peak electric for local transport, with a generator assist engine to increase range.
Wow RR, you are really a creative thinker. Dude, once you’ve completed your gig in Scotland, you consider should talking to Khosla and getting funding for a start-up. Even though you guys have disagreed about ethanol, you have a common high-level objective and it sounds like he has respect for your abilities.
Well thats the trick though.
It’s not “Fuel or Food”
It’s actually “Fuel or Rainforrest”
And “Fuel versus Foodmiles”
Since areas like Brazil, Indonesia, and Argentia are trying to become the breadbaskets of the world.
And consequently leveling whatever tropical forrests get in their way.
http://greyfalcon.net/ran
http://greyfalcon.net/soy
http://greyfalcon.net/soy2
http://greyfalcon.net/palmoil
http://greyfalcon.net/peat
They will be more than happy to have other countries despoil their land, and buy their wares.
The other catch to add into there is that the “Food miles” skyrocket.
All in all, not good news from a greenhouse perspective.
But it’s never really going to be “Fuel versus Food”, or atleast given some time for market adjustment.
What you really have to worry about is what happens after that has been “solved”.
Biological processes are slow, but efficient.
No – they are not:
1. Much of the feedstock is left unconverted. Conventional ethanol fermenting yeast can only live of sugars. Part of the difficulty is converting cellulose into sugar, without destroying the sugar. Much of the remaining organics (lignin) cannot be converted into sugars.
2. Part of the feedstock goes into creating the fermenting biomass (typically yeast). While great claims are made about using that for feed, it subtracts from the feedstock available for fuel production.
As I have stated before, I don’t think fermentative technology (excluding anaerobic digestion) can make a significant contribution. When there are enzymes involved, I’m twice as skeptical.
King, you and Robert both know a lot about the conventional oil business, and related technologies like gasification. But you both seem to overestimate the efficiencies of the technologies you don’t know – you with fermentation, he with renewable electric. Just because the technologies you do know seem to have low efficiencies, does not mean the unknown can beat it…
Interesting article, Robert!
Not sure that cows don’t have the digestive capabilities to live on wood, maybe they just lack the (beaver-like) teeth to ingest the wood. Now there’s an idea for genetic egineering: a cow with beaver teeth! Make sure you have all steel fencing, though…
Back in the day, my grandfather made me a toy that consisted of a stick, a piece of string tied to the end of it and a small piece of wood tied to the end of the string. When you swung the piece of wood through the air it would make a whirr sound, similar to the device the Aborigines use in the Chrocodile Dundee movies.
One day I had this toy with me and there were some calves around. Next thing I know, a calf had grazed down the piece of wood, and had the string still dangling from its mouth. I carefully pulled out the string, but the piece of wood was gone! The string was still tied, so it did not just slip off. Only thing I can think was that the calf recognized the piece of wood as food, and that his rumen agreed!
We’ll see if this research goes anywhere. I have my doubts, as noted above.
4.45E+09 acres wood needed to replace oil
6.95E+06 sq miles of wood needed to replace oil
126 number of Iowas** (at 55k sq miles/Iowa)
It’s not about replacing oil. As I have said before, I don’t think biomass is capable of replacing our current usage of oil. I think we have a chance of maintaining a decent standard of living by electrifying our automobile transportation and producing the electricity from a combination of coal, nuclear, and natural gas – while shifting over time to an ever greater proportion of renewable electricity. Of course a great big dose of conservation would help immensely to achieve this.
But we will still need some liquid fuels for things like airline and long-haul transport. Therefore, you need some liquid fuel options, but not enough to displace all the oil we use. And if you are going to produce that liquid fuel from cellulose, we need a different approach than the acid-hydrolysis or steam explosion route we are currently going down. That will never be cost effective.
Wired magazine put a very sneering response in the “letters” section of this issue, responding to letters about their previous “cellulosic is our future” issue. Check it out if you have a copy handy.
Biological processes are slow, but efficient.
No – they are not:
I meant efficient in a relative sense. Fermentation, anaerobic digestion, etc. doesn’t consume large amounts of energy up-front to maintain the process when compared to gasification. Even so, a large amount of enery is required to seperate the fuel from the water required for fermentation or digestion.
I agree with you, that biofuels are at best a very small contributor.
The law of unintended consequences applies here. There is just no way to make biofuels without raising the cost of food, even on a local scale. We are having a big problem with metal recycling. As the price of copper has gone up, thieves are taking A/C units, street lights, architectural pieces and just about anything of any value. Food prices have to rise to keep the crops or land out of fuel production.
RR,
Yes, I agree it isn’t about replacing oil…and I would not want to prevent private R&D from working on it.
I’m more worried about another publically-funded ethanol-from-corn boondoggle. We both know that private industry would never have gone beyond the lab and maybe a few small-scale proof-of-concept plants.
That’s a fine, measured approach for exploring alternative energy sources–and exactly the sort of prudence people exhibit when it is their own money on the line.
And that is what we need with a termite-gut or cow-gut approach. If it shows any sort of promise, then venture capital will be all over it like buzzards on sh–wagon. Big Oil will toss E&P bucks at it once it can compete with oil, and we all win. (of course, if it can never compete with oil on a $/btu basis–even in a Peak Lite scenario–then it is not an energy source worth having).
All that said, I just don’t see the Btu/acre working out for anything that grows, regardless how you suck energy out of it. Not even with the magic switchgrass. It just uses too much damn land and water, not even getting to the transport & processing costs.
And to answer the person above who said it won’t always be a food vs. fuel issue — think about it a little harder. If the land doesn’t grow food very well, it won’t grow fuel very well. It *will* be a food vs. fuel issue. Arable land is arable land, and desert plants grow slowly for a reason.
What will happen is:
(a) oil/nat gas will get expensive. Sooner or later the demand curve will show some elasticity. Consumption will drop just like it did around 30 years ago. It hasn’t yet b/c our standard of living is so damn high we still pay $6 for coffee and buy new electronics every year. CPI has not even come close to keeping up with wages + benefits — have you been following the Soc Sec debates about benefits?
(b) deepwater drilling will get pretty good, but always expensive, delaying the inevitable but keeping oil prices higher than we’re used to (spoiled brats that we are). There’s lots of ocean out there….and have you seen the stuff coming on line? Lots of new deepwater drill ships coming on line. More will come if oil stays pricey, i.e., scarce.
(c) king coal will rise again, further delaying the inevitable
(d) fission? not sure. Just how much fissile material is out there waiting to be mined? Reprocessing only delays the inevitable. No, you can’t magically make more fuel. Sooner or later your are going to end up with isotopes that are in the wrong part of the binding energy curve.
(e) energy efficiency becomes economically sound (e.g., no need for CAFE standards when gasoline or its equivalent is $15/gallon). That’s when “conservation” really starts.
Yes, there was a point to this ramble: sooner or later, over the next couple hundred years, someone figures out a home-run solution.
Until then, energy will be produced in small batches from a variety of expensive sources (solar, geothermal, biomass, tidal, etc.) and used very, very carefully–simply because it costs alot.
Your termites will be quite valuable in that scenario. It just can’t play out until Btus get so expensive that it is worth “burning food.”