Featured Research

from universities, journals, and other organizations

New advanced biofuel identified as an alternative to diesel fuel

Date:
September 28, 2011
Source:
DOE/Lawrence Berkeley National Laboratory
Summary:
Researchers have identified a terpene called bisabolane as a potential biofuel for replacing diesel fuel. The researchers have also engineered two strains of microbes -- a bacteria and a yeast -- that can be used in the biosynthetic production of this clean, green, renewable and domestic alternative to diesel fuel.

From left, Pamela Peralta-Yahya, Taek Soon Lee and Mario Ouellet were key members of a team at the Joint BioEnergy Institute (JBEI) that demonstrated the potential of the chemical compound bisabolane to replace D2 diesel.
Credit: Photo by Roy Kaltschmidt, Berkeley Lab

Researchers with the U.S Department of Energy (DOE)'s Joint BioEnergy Institute (JBEI) have identified a potential new advanced biofuel that could replace today's standard fuel for diesel engines but would be clean, green, renewable and produced in the United States.

Using the tools of synthetic biology, a JBEI research team engineered strains of two microbes, a bacteria and a yeast, to produce a precursor to bisabolane, a member of the terpene class of chemical compounds that are found in plants and used in fragrances and flavorings. Preliminary tests by the team showed that bisabolane's properties make it a promising biosynthetic alternative to Number 2 (D2) diesel fuel.

"This is the first report of bisabolane as a biosynthetic alternative to D2 diesel, and the first microbial overproduction of bisabolene in Escherichia coli and Saccharomyces cerevisiae," says Taek Soon Lee, who directs JBEI's metabolic engineering program and is a project scientist with Lawrence Berkeley National Laboratory (Berkeley Lab)'s Physical Biosciences Division. "This work is also a proof-of-principle for advanced biofuels research in that we've shown that we can design a biofuel target, evaluate this fuel target, and produce the fuel with microbes that we've engineered."

Lee is the corresponding author of a paper reporting this research in the journal Nature Communications. Co-authoring this paper were Pamela Peralta-Yahya, Mario Ouellet, Rossana Chan, Aindrila Mukhopadhyay and Jay Keasling.

The rising costs and growing dependence upon foreign sources of petroleum-based fuels, coupled with scientific fears over how the burning of these fuels impacts global climate, are driving the search for carbon-neutral renewable alternatives. Advanced biofuels -- liquid transportation fuels derived from the cellulosic biomass of perennial grasses and other non-food plants, as well as from agricultural waste -- are highly touted for their potential to replace gasoline, diesel and jet fuels. Unlike ethanol, which can only be used in limited amounts in gasoline engines and can't be used at all in diesel or jet engines, plus would corrode existing oil pipelines and tanks, advanced biofuels are drop-in fuels compatible with today's engines, and delivery and storage infrastructures.

"We desperately need drop-in, renewable biofuels that can directly replace petroleum-derived fuels, particularly for vehicles that cannot be electrified," says co-author Keasling, CEO of JBEI and a leading authority on advanced biofuels. "The technology we describe in our Nature Communications paper is a significant advance in that direction."

JBEI is one of three Bioenergy Research Centers established by the DOE's Office of Science in 2007. Researchers at JBEI are pursuing the fundamental science needed to make production of advanced biofuels cost-effective on a national scale. One of the avenues being explored is sesquiterpenes, terpene compounds that contain 15 carbon atoms (diesel fuel typically contains 10 to 24 carbon atoms).

"Sesquiterpenes have a high-energy content and physicochemical properties similar to diesel and jet fuels," Lee says. "Although plants are the natural source of terpene compounds, engineered microbial platforms would be the most convenient and cost-effective approach for large-scale production of advanced biofuels."

In earlier work, Lee and his group engineered a new mevalonate pathway (a metabolic reaction critical to biosynthesis) in both E. coli and S. cerevisiae that resulted in these two microorganisms over-producing a chemical compound called farnesyl diphosphate (FPP), which can be treated with enzymes to synthesize a desired terpene. In this latest work, Lee and his group used that mevalonate pathway to create bisabolene, which is a precursor to bisabolane.

"We proposed that the generality of the microbial FPP overproduction platforms would allow for the biosynthesis of sesquiterpenes," Lee says. "Through multiple rounds of large-scale preparation in shake flasks, we were able to prepare approximately 20 milliliters of biosynthetic bisabolene, which we then hydrogenated to produce bisabolane."

When they began this work, Lee and his colleagues did not know whether bisabolane could be used as a biofuel, but they targeted it on the basis of its chemical structure. Their first step was to perform fuel property tests on commercially available bisabolene, which comes as part of a mixture of compounds. Convinced they were onto something, the researchers then used biosynthesis to extract pure biosynthetic bisabolene from microbial cultures for hydrogenation into bisabolane. Subsequent fuel property tests on the bisabolane were again promising.

"Bisabolane has properties almost identical to D2 diesel but its branched and cyclic chemical structure gives it much lower freezing and cloud points, which should be advantageous for use as a fuel," Lee says. "Once we confirmed that bisabolane could be a good fuel, we designed a mevalonate pathway to produce the precursor, bisabolene. This was basically the same platform used to produce the anti-malarial drug artemisinin except that we introduced a terpene synthase and further engineered the pathway to improve the bisabolene yield both in E. coli and yeast."

Lee and his colleagues are now preparing to make gallons of bisabolane for tests in actual diesel engines, using the new fermentation facilities at Berkeley Lab's Advanced Biofuels Process Demonstration Unit. The ABPDU is a 15,000 square-foot state-of-the art facility, located in Emeryville, California, designed to help expedite the commercialization of advanced next-generation biofuels by providing industry-scale test beds for discoveries made in the laboratory.

"Once the complete fuel properties of hydrogenated biosynthetic bisabolene can be obtained, we'll be able to do an economic analysis that takes into consideration production variables such as the cost and type of feedstock, biomass depolymerization method, and the microbial yield of biofuel," Lee says. "We will also be able to estimate the impact of byproducts present in the hydrogenated commercial bisabolene, such as farnesane and aromatized bisabolene."

Ultimately, Lee and his colleagues would like to replace the chemical processing step of bisabolene hydrogenation with an alkene reductase enzyme engineered into the E. coli and yeast so that all of the chemistry is performed within the microbes.

"Enzymatic hydrogenation of this type of molecule is a very challenging project and will be a long term goal," Lee says. "Our near-term goal is to develop strains of E. coli and yeast for use in commercial-scale fermenters. Also, we will be investigating the use of sugars from biomass as a source of carbon for producing bisabolene."


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. Pamela P. Peralta-Yahya, Mario Ouellet, Rossana Chan, Aindrila Mukhopadhyay, Jay D. Keasling, Taek Soon Lee. Identification and microbial production of a terpene-based advanced biofuel. Nature Communications, 2011; 2: 483 DOI: 10.1038/ncomms1494

Cite This Page:

DOE/Lawrence Berkeley National Laboratory. "New advanced biofuel identified as an alternative to diesel fuel." ScienceDaily. ScienceDaily, 28 September 2011. <www.sciencedaily.com/releases/2011/09/110927134254.htm>.
DOE/Lawrence Berkeley National Laboratory. (2011, September 28). New advanced biofuel identified as an alternative to diesel fuel. ScienceDaily. Retrieved August 29, 2014 from www.sciencedaily.com/releases/2011/09/110927134254.htm
DOE/Lawrence Berkeley National Laboratory. "New advanced biofuel identified as an alternative to diesel fuel." ScienceDaily. www.sciencedaily.com/releases/2011/09/110927134254.htm (accessed August 29, 2014).

Share This




More Matter & Energy News

Friday, August 29, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Australian Airlines Relax Phone Ban Too

Australian Airlines Relax Phone Ban Too

Reuters - Business Video Online (Aug. 26, 2014) Qantas and Virgin say passengers can use their smartphones and tablets throughout flights after a regulator relaxed a ban on electronic devices during take-off and landing. As Hayley Platt reports the move comes as the two domestic rivals are expected to post annual net losses later this week. Video provided by Reuters
Powered by NewsLook.com
Hurricane Marie Brings Big Waves to California Coast

Hurricane Marie Brings Big Waves to California Coast

Reuters - US Online Video (Aug. 26, 2014) Huge waves generated by Hurricane Marie hit the Southern California coast. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
Chinese Researchers Might Be Creating Supersonic Submarine

Chinese Researchers Might Be Creating Supersonic Submarine

Newsy (Aug. 26, 2014) Chinese researchers have expanded on Cold War-era tech and are closer to building a submarine that could reach the speed of sound. Video provided by Newsy
Powered by NewsLook.com
Breakingviews: India Coal Strained by Supreme Court Ruling

Breakingviews: India Coal Strained by Supreme Court Ruling

Reuters - Business Video Online (Aug. 26, 2014) An acute coal shortage is likely to be aggravated as India's supreme court declared government coal allocations illegal, says Breakingviews' Peter Thal Larsen. 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.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

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