BIO Pushes for Cellulosic Ethanol
17 March 2006
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| Cellulase enzymes will play a critical role in the enabling of the production of cellulosic ethanol. |
BIO, the Biotechnology Industry Organization, organized a panel in Washington this week to describe the industrial biotechnology processes that enable large-scale production of cellulosic ethanol from biomass such as crop waste and switch grass. The panel included representatives from biotech and biofuel firms Diversa, Novozymes and Abengoa Bioenergy, as well as BIO itself and the Natural Resources Defense Council (NRDC).
Panelists at the event described how industrial biotechnology—called the third wave in biotechnology innovation—is using novel biotech tools to identify or improve enzymes from microbes for use in converting the hard, fibrous content of plants, primarily cellulose and lignin, to sugars.
The resulting sugars can then be fermented by biotech-improved bacteria to make ethanol transportation fuel or biobased plastics. Recently completed research on enzymes makes possible large-scale production of cellulosic ethanol from dedicated energy crops—such as switch grass—or crop wastes such as corn stover and wheat straw or rice straw at a cost competitive with that of petroleum-based fuels.
Industrial biotech is the enabling technology that will allow farmers to harvest two crops from every field—a food crop and a biomass crop for fuel production. Biotech breakthroughs mean that the nation’s breadbasket could also become the energy fields of the United States. The question is not when, but how soon this will happen.
—Brent Erickson, BIO EVP for industrial and environmental biotechnology
Diversa has partnered with a consortium including DuPont, Deere & Co., the National Renewable Energy Laboratory and Michigan State University to develop a biorefinery that can produce ethanol and other products from the entire corn plant, integrating traditional grain-based ethanol production with cellulosic ethanol production from stalks and husks.
Diversa has already introduced a new alpha-amylase enzyme designed to improve the efficiency and economics of corn ethanol production. The new “Ultra-Thin” enzyme operates at high temperature and at a lower pH than other commercially available enzymes—a combination grain ethanol producers have been seeking for years. (Earlier post.)
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| A key enabler of cellulosic ethanol? Source: Diversa. |
The company, along with CalTech, INBio and the DOE Joint Genome Institute, is now investigating the use of enzymes produced in microbes in termite guts to accelerate the production of cellulosic ethanol.
Termites eat wood and convert it to sugar by exploiting the metabolic capabilities of microbes inhabiting their hindguts. Conversion is fast and efficient: 95% in 24 hours or less. Once the cellulose is converted to sugar, it can be fermented.
Diversa is working on optimizing new enzymes from these sources via its directed evolution process to perform on specific cellulosic biomass feedstocks and in specific industrial conditions.
Novozymes. Enzyme cost has been a significant barrier to the production of cellulosic ethanol. In 2001, the enzyme costs as around $5.40/gallon—the most significant single cost. Through research funded by the DOE and NREL, Novozymes has successfully reduced the enzyme cost 30 fold&madsh;down to $0.10-0.18/gallon.
Enzyme cost is only one element of the process, however, and now that those costs are coming down, Novozymes is looking for improvements in the other portions of hte process: collection and storage; pre-treatment; plant and process design; yeast; and distribution and formulation.
While the private sector is making great strides in developing new biotech processes, public sector assistance must help solve technical issues and help to integrate the various parts of the value chain, according to the company.
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| Site of the cellulosic ethanol plant—next to a conventional ethanol plant. |
Abengoa Bioenergy began construction of the world’s first commercial scale cellulosic ethanol plant in August 2005. (Earlier post.)
Upon its completion in 2006, the plant will process 70 tonnes of agricultural resides, such as wheat straw, every day, producing more than 1 million gallons of cellulosic ethanol annually.
This has to be one of the ways to go for energy security.
Growing human edible crops to ferment to ethanol is pandering to farmers. We need fuel crops, not animal feed, and we need something that can scale up easily.
If you look at the amount of mineral oil we are consuming, we have a huge task ahead of us.
What we need is a "land+water+sun+co2 -> liquid fuel" cycle.
As long as we can get a current engine to burn the fuel, cleanly, we have a solution.
We could skip hydrogen completly in this case.
We will have to make cars more efficient, but expensive fuel should make this happen - one way or another.
One thing strikes me - perhaps the EPA should back off on emissions and put pressure on efficiency instead. There is only so much the car manufacturers can do to their engines / development cycle and it is now time to concentrate on efficiency. Emissions are probably good enough at this stage.
Posted by: mahonj | 18 March 2006 at 03:36 AM
I'm sure others have said this before but a great product would be one that converted grass clippings and leaves into ethanol.
Posted by: VaPrius | 18 March 2006 at 03:44 AM
We already have a great system that converts food into energy. It's called the human body.
Walk. Ride a bicycle. Walk to the bus. Walk from the bus. Walk to the metro. Walk from the metro. I know. It's not the answer. People would have to live closer to where they shop and work. People would have to get off their duff. But it could be a big part of the answer.
Posted by: t | 18 March 2006 at 07:14 AM
"t" makes a very good observation. In my personal experience over the past 10 years, I've calculate my effective miles per gallon at roughly 100 mpg. (Total miles traveled/total gallons of gasoline purchased). I ride my bicycle to work/shopping/etc. when practicable, other times I take my scooter (avg 80 mpg), other times car pool (30mpg x 2 passengers), and other times drive my car without passengers (30mpg). By working at home two days a week, I automatically improve mpg and associated ecological impact reduction by 40%, as compared to driving my car to work 5 days a week. The upshot: There are other options to technology improvements that will haul the american fat ass from one end of the parking lot to the other, that can result in energy efficiency improvement. A few simple changes in personal behavior also can result in impressive outcomes. My 10 year 100mpg was achieved without plug ins, hybrids, fuel cells, cold fusion mumbo jumbo, etc. I've spent ZERO dinero buying the latest whiz bang $25k+ hybrid. Thus, the problem with my 100mpg approach, is that it does not bode well for car makers, burger king, the mall of america, Walmart, etc.
Posted by: john galt | 18 March 2006 at 08:41 AM
John Galt.
Good for you. And another thing. I used to live 5 miles from work and bicycled every day to work. Total time spent: 1 hour. I killed two birds with one stone. If I had driven to work, I would have still needed to get the exercise. Total time spent: an hour and a half. Not to mention possible health club costs.
Posted by: t | 18 March 2006 at 10:06 AM
Bicycles are definitely a sensible way to cover short distances if the weather is not too hot or too humid, you have time (and no gids/elderly parents/heavy stuff) to transport and the terrain is not too steep. It also helps if your employer can offer a shower and a locker for your laundry. Bikes with electric assist motors are expensive, but they let you get to work on time and refreshed and exercise on the way back. Bike lanes are smart, too.
For many transportation tasks, however, you'll still want/need a motor vehicle. By all accounts, ethanol from cellulose appears to offer singificant cost reductions over ethanol from foodstuffs (e.g. corn). I hope the companies involved succeed in scaling up their technology.
Mahonj makes a good point about emissions vs. fuel economy. The former are certainly important to curb respiratory ailments due to NOx and PM as well as cancer risk due to HC. However, all developed countries are by now well into the realm of rapidly diminishing returns. The legislative effort has simply taken on a life of its own, and no politician is willing to relax pollution limits in order to enable better fuel economy (e.g. through diesel engines, cp. Europe). Improved fuel economy is also a prerequisite for biofuels to make a serious dent in US dependence on oil from more-or-less hostile sources.
Posted by: Rafael Seidl | 18 March 2006 at 11:11 AM
Great ideas. Now all we need to do is force corporate executives, construction workers, doctors, lawyers, and long haul truckers to use bikes. A bit of a challenge, but I think we can do it!
Posted by: S | 18 March 2006 at 11:58 AM
John Galt, a character from Atlas Shrugged, advocated letting other people's children starve to death.
Posted by: tom deplume | 18 March 2006 at 02:13 PM
For the record, I cycle 9 miles to work every day (unless I am sick) and 9 miles back. I do have a locker and shower at work (!) - essential if you are not to work alone.
It is by far the best way for individual people to commute for short-medium distances in temperate climates (Ireland in my case), but most people just won't do it.
I despair at how to get people to use this form of transport. Some people in Europe: Holland, Demmark, seem to have go over the "car is best" view, but the rest of the planet seems to consider it essential to bring 1.3 tons of metal to work with you every day.
It is a hearts and minds problem more than an engineering one, imho.
Getting cellulosic ethanol to work, on the other hand is very much an engineering problem that is well worth working on (like better batteries) and we could all benefit from its solution.
Posted by: mahonj | 18 March 2006 at 02:48 PM
If you're in the climate for it, there's always a scooter.
I get 70+ mpg on my Honda Reflex 250.
Posted by: Cervus | 18 March 2006 at 11:23 PM
I grew up in Miami and now spend most of my time in Boston. I owned a bike in both places, but in each instance, due to the climate, it was frequently impractical to use it. Not to mention the fact that I hit a pothole last week and crashed, damaging my present bike. This afternoon I took the bus from my place to visit a friend across town -- about 3 miles away. We both live in central urban neightborhoods. It took about 45 minutes, door-to-door. In the evening, I got a ride home in a car. It took less than ten.
I support better public transportation, and enjoy living in interesting urban environments. I like being able to walk places, and having a neighborhoods worth walking in. I don't find dispersed suburban monotony all that appealing. But I also know that rapid, personal mobility is an incredible boon, and often a practical necessity. I also know that the ways in which we have been providing that to ourselves are not sustainable over the long term.
I am assuming that most of those who surf this website recognize those same pragmatic issues. This is, after all, Green Car Congress, not Abolish Cars Congress. Many of us should probably drive less. Many of us should be driving smaller cars or carpooling more often. Few of us could do without driving at all.
As to the issue at hand -- it seems that this could be a major game-player in the short to medium term future. Ethanol is largely compatible with existing automotive designs and technologies. It is a proven technology here in the United States, and Brazil has been running largely on ethanol for years. Does anyone have any notion of how much cellulostic farm waste we have, and how much ethanol would could make simply on our current agricultural production?
I wonder what do we currently do with all the waste biomass which would be used for producing ethanol. Do farmers use it as a sort of fertilizer? If so, what would be the costs of replacing it?
Posted by: NBK-Boston | 19 March 2006 at 12:45 AM
Noticably missing from this panel is BRI Energy, LLC which employs syngas fermentation to convert cellulosic feedstock to ethanol.
The companies listed use enzymatic hydrolysis which involves developing (to date) expensive enzymes to breakdown the feedstock to sugars before using conventional fermentation processes to distill the sugars to ethanol. The problem I see with that is that: 1) each feedstock requires enzymes customized for it, 2) the feedstock cannot be blended and 3) the process takes a long time (days).
The BRI process goes a revolutionary way. It gasifies the feedstock which means that the feedstock can be pure or blended with a range of biomass (and even coal or other fossil fuels) to generate heat (used to cogenerate electricity) and syngas which can then be bio converted to ethanol. How? The syngas is fed to anerobic bacteria in a special fermenting chamber that eats up the gas and secretes ethanol. The process takes about 7 minutes. Zero emissions with benign purge and ash.
I believe BIO is right - cellulosic ethanol is the way to go. But they should seat syngas fermentation technology on the panel. I strongly favor expediting commercial scaling of the BRI pilot plant over any of those mentioned in this article. My sources tell me construction will probably begin this summer.
Posted by: C. Scott Miller | 19 March 2006 at 10:03 PM
The problem with the gasification process is that it loses a great deal of energy as heat. This is good if you want to make electricity, not so good if you've got other sources of juice and really need liquid fuel.
Of course, the problem with liquid fuel is that it just enables our current 14.9% efficient vehicle fleet to keep on being wasteful. If we carbonized the biomass (~50% efficiency plus off-gas) and fed the charcoal to direct-carbon fuel cells (80%) we'd have more than twice the overall efficiency (probably better than 3 times considering byproducts).
Posted by: Engineer-Poet | 20 March 2006 at 01:15 AM
C. Scott Miller,
You make an excellent point. Why bother with fermentation if you can have syngas? But let me take it one step further: once you have syngas, why convert it to ethanol (and even if you did, why use a biological process?).
I believe a better solution is using Fischer-Tropsch to convert syngas into hydrocarbons. This way you get a fuel that is identical to today's fuels (i.e. can be blended at any ratio), you avoid the energy intensive distillation to separate ethanol from water, the product has low vapor pressure (low emissions) and is not hygroscopic. Basically, you have all the benefits of existing fuel supplies (and the ability to use existing infrastructure unchanged). Plus, your fuel is cleaner than todays fuels (no sulfur, no aromatics).
I am in favor of persuing cellulosic ethanol - it makes a lot more sense than corn ethanol - but I think gasification/F-T will beat it at the end of the day.
Posted by: An Engineer | 20 March 2006 at 10:49 AM
The problem with the gasification process is that it loses a great deal of energy as heat.
This problem is actually an advantage. The heat doesn't have to come from combustion of the biomass; it can be added from another source. For example, there is a waste-to-ethanol project being planned in New Jersey where the gasification will be done with a plasma torch. The electrical energy can come from non-fossil sources, such as nuclear or wind, so this maximizes the fraction of carbon atoms in the feedstock that end up in ethanol.
That project, btw, will convert the syngas to ethanol using a non-biological catalyst, which is a variant of Fischer-Tropsch using a sulfide catalyst that is very tolerant of sulfur in the syngas. This is unlike conventional iron or cobalt-based FT catalysts that are poisoned by too much sulfur.
The big advantage of gasification for bio-ethanol production is it lets you use the carbon in lignin, which the traditional starch or cellulose routes can't handle. In those schemes, the lignin gets burned anyway.
Posted by: Paul Dietz | 20 April 2006 at 08:33 AM
the comments and subject is highly appreciable. Can u please tell me wether this process may be conducted at farmers level?
Please pass on the references for the same and your views, all of them to this E-mail ID>
Posted by: Dr rudraswamy | 07 February 2007 at 11:52 PM