Featured Research

from universities, journals, and other organizations

More bang for the biofuel buck

November 8, 2012
DOE/Lawrence Berkeley National Laboratory
Researchers have shown that a fermentation process used in World War I to make cordite for bullets and artillery shells, in combination with a modern palladium catalyst could produce gasoline, diesel or jet fuel from the sugars found in biomass.

The fermentation process used in World War I to make cordite for bullets and artillery shells might find new use today in the production of advanced biofuels.
Credit: Image courtesy of DOE/Lawrence Berkeley National Laboratory

A fermentation technique once used to make cordite, the explosive propellant that replaced gunpowder in bullets and artillery shells, may find an important new use in the production of advanced biofuels. With the addition of a metal catalyst, researchers at the U.S. Department of Energy (DOE)'s Lawrence Berkeley National Laboratory (Berkeley Lab) have shown that the production of acetone, butanol and ethanol from lignocellulosic biomass could be selectively upgraded to the high volume production of gasoline, diesel or jet fuel.

Related Articles

Using the bacterium Clostridium acetobutylicum, the Berkeley Lab researchers fermented the sugars found in biomass into the solvent acetone and the alcohols butanol and ethanol, collectively known as "ABE" products. They then catalyzed these low carbon number products with the transition metal palladium into higher-molecular-mass hydrocarbons that are possible precursors to the three major transportation fuel molecules. The specific type of fuel molecule produced -- whether a precursor to gasoline, diesel or jet -- was determined by the amount of time the ABE products resided with the palladium catalyst.

"By catalytically upgrading ABE fermentation products we're able to exploit highly efficient metabolic pathways and achieve near theoretical yields of transportation fuel precursors," says Dean Toste, a chemist who holds joint appointments with Berkeley Lab and the University of California (UC) Berkeley. "With our technique, we can obtain about a gallon of fuel from 16 pounds of the sugars that can be derived from lignocellulosic biomass."

Toste is the corresponding author of a paper published in the journal Nature titled "Integration of chemical catalysis with extractive fermentation to produce fuels." Co-authoring this paper were Pazhamalai Anbarasan, Zachary Baer, Sanil Sreekumar, Elad Gross, Joseph Binder, Harvey Blanch and Douglas Clark. The work was supported by the Energy Biosciences Institute (EBI), a collaborative partnership between UC Berkeley, Berkeley Lab and the University of Illinois at Urbana Champaign. EBI is funded by the BP energy corporation.

Clostridium acetobutylicum is also known as the Weizmann organism after Chaim Weizmann, the chemist who first used the bacterium to ferment ABE products from starch. The bacterium rose to prominence during World War I when it was used by the British to ferment acetone for the production of cordite. C. acetobutylicum and the ABE fermentation process continued to be widely used until the 1950s when they were replaced by cheaper petrochemical-based processes.

With rising concerns about the release of excess carbon into the atmosphere as the result of burning fossil fuels, there is a renewed scientific effort to develop advanced biofuels for transportation energy. Synthesized from the sugars in the lignocellulosic biomass of grasses and other non-food plants, and produced in a sustainable manner, advanced biofuels could be carbon-neutral, meaning their use would not add excess carbon to the atmosphere. In addition, they would be renewable and non-polluting and represent a huge potential source of domestic jobs and revenue. Furthermore, unlike ethanol made from corn starch or sugarcane, advanced biofuels, if they could be successfully developed and produced cost-effectively, could be dropped into today's vehicles with presumably with no impact on performance, and used in today's infrastructures with no modifications required.

"In some ways, this work is a step back in time in which a very old fermentation process is being used with some new engineering and chemistry," says co-author Blanch, one of the nation's deans of biofuels research who also holds joint appointments with Berkeley Lab and UC Berkeley. "While there has been some progress in engineering microbes to produce advanced biofuels, the quantities produced thus far -- technically, the solution's titer -- tend to be very limited. A hybrid method, combining microbial production with chemical catalysis, might provide a pathway to more efficient production of these advanced biofuels."

C. acetobutylicum ferments the sugars in lignocellulosic biomass into a product that is three parts acetone, six parts n-butanol, and one part ethanol, similar to how yeast ferments the sugars in grapes and hops into wine and beer. From a transportation energy perspective, the two-carbon chains of ethanol, three-carbon chains of acetone and four-carbon chains of butanol are mainly useful as additives to gasoline. However, the production of acetone in combination with the alcohols makes it possible to build longer hydrocarbons chains of gasoline, diesel and jet fuel.

"The key to our technology is the ability of C. acetobutylicum to produce acetone," Toste says. "Acetone harbors a nucleophilic alpha-carbon, which is amenable to the formation of carbon bonds with the alcohols produced in ABE fermentation."

To catalyze the build-up of these shorter carbon chains into longer fuel chains -- a process called "alkylation" -- Toste and his co-authors tested a number of transition metal catalysts, the workhorses of modern industry that are used to initiate virtually every industrial manufacturing process involving chemistry. The best performer they tested was palladium.

"In the first reactor, we remove the low-boiling ABE products from the fermentation broth using a high-boiling extractant, such as glyceryl tributyrate," Toste says. "This removes toxic products from the organism, allowing for higher yields of ABE and a clean stream of product for chemical catalysis, which takes place in a second reactor. While palladium on carbon was the best catalyst in these tests, we have already identified other transition metal catalysts that could be even better."

Toste believes that the integrative biological/chemical approach he and his colleague are reporting should be relatively simple to scale-up and implement on a commercial scale.

"The ABE fermentation process was established and scaled nearly a century ago," he notes, "and while the chemistry portion is less proven on scale, it relies on heterogeneous catalysis, a mainstay of industrial chemistry today."

Toste believes the combination of biological fermentation and chemical catalysis has important potential applications beyond the conversion of lignocellulosic biomass into transportation fuels and could become a powerful new technology-enabling tool.

"Many technologies today rely on either fermentation or chemical catalysis," he says. "The idea of building integrated fermentation processes involving networks of catalysts is an exciting prospect."

Adds co-author Blanch, "Integrating chemistry and fermentation is a useful way to capitalize on the best of both worlds. The chemistry described in our Nature paper is exciting because new carbon-carbon bonds are being formed between molecules and oxygen is being rejected without the need of hydrogenation. This results in very high yields."

This research was funded by the Energy Biosciences Institute.

Story Source:

The above story is based on materials provided by DOE/Lawrence Berkeley National Laboratory. Note: Materials may be edited for content and length.

Journal Reference:

  1. Pazhamalai Anbarasan, Zachary C. Baer, Sanil Sreekumar, Elad Gross, Joseph B. Binder, Harvey W. Blanch, Douglas S. Clark, F. Dean Toste. Integration of chemical catalysis with extractive fermentation to produce fuels. Nature, 2012; 491 (7423): 235 DOI: 10.1038/nature11594

Cite This Page:

DOE/Lawrence Berkeley National Laboratory. "More bang for the biofuel buck." ScienceDaily. ScienceDaily, 8 November 2012. <www.sciencedaily.com/releases/2012/11/121108181719.htm>.
DOE/Lawrence Berkeley National Laboratory. (2012, November 8). More bang for the biofuel buck. ScienceDaily. Retrieved April 21, 2015 from www.sciencedaily.com/releases/2012/11/121108181719.htm
DOE/Lawrence Berkeley National Laboratory. "More bang for the biofuel buck." ScienceDaily. www.sciencedaily.com/releases/2012/11/121108181719.htm (accessed April 21, 2015).

Share This

More From ScienceDaily

More Earth & Climate News

Tuesday, April 21, 2015

Featured Research

from universities, journals, and other organizations

Featured Videos

from AP, Reuters, AFP, and other news services

Going Ape: Sierra Leone Chimpanzees Hail Ebola Retreat

Going Ape: Sierra Leone Chimpanzees Hail Ebola Retreat

AFP (Apr. 21, 2015) As money runs out at Tacugama Chimpanzee Sanctuary in Sierra Leone, around 85 chimps are facing homelessness. The centre closed when the Ebola epidemic was ravaging the country but now that closure is beginning to look permanent. Video provided by AFP
Powered by NewsLook.com
Wild Weather Lashes Sydney Region

Wild Weather Lashes Sydney Region

AFP (Apr. 21, 2015) Sydney and surrounding areas are lashed by wild weather with trees felled, power cuts hitting thousands of homes and sand drifts sweeping inland off the iconic Bondi beach. Duration: 00:50 Video provided by AFP
Powered by NewsLook.com
Deepwater And Dolphins: The Oil Spill's Impact 5 Years On

Deepwater And Dolphins: The Oil Spill's Impact 5 Years On

Newsy (Apr. 20, 2015) Five years on, the possible environmental impact of the Deepwater Horizon spill includes a sustained die-off of bottlenose dolphins, among others. Video provided by Newsy
Powered by NewsLook.com
Pee-Power Toilet to Light Up Disaster Zones

Pee-Power Toilet to Light Up Disaster Zones

Reuters - Innovations Video Online (Apr. 20, 2015) Students and staff are being asked to use a prototype urinal to &apos;donate&apos; urine to fuel microbial fuel cell (MFC) stacks that generate electricity to power lighting. The developers hope the pee-power technology will light toilet cubicles in refugee camps, where women are often at risk of assault in poorly lit sanitation areas. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.


Breaking News:

More Coverage

Sweet Diesel: Discovery Resurrects Process to Convert Sugar Directly to Diesel

Nov. 7, 2012 Nearly 100 years ago, a chemist discovered that Clostridium bacteria efficiently ferment sugar or starch into alcohols and acetone. Cheap fossil fuels made the process commercially unviable, but it ... read more

Strange & Offbeat Stories

Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News


Free Subscriptions

Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile

Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?

Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins