Featured Research

from universities, journals, and other organizations

Engineered plants make potential precursor to raw material for plastics

Date:
November 9, 2010
Source:
DOE/Brookhaven National Laboratory
Summary:
Scientists report engineering a plant that produces industrially relevant levels of compounds that could potentially be used to make plastics.

Researchers report engineering a plant that produces industrially relevant levels of compounds that could potentially be used to make plastics.
Credit: Image courtesy of DOE/Brookhaven National Laboratory

In theory, plants could be the ultimate "green" factories, engineered to pump out the kinds of raw materials we now obtain from petroleum-based chemicals. But in reality, getting plants to accumulate high levels of desired products has been an elusive goal. Now, in a first step toward achieving industrial-scale green production, scientists from the U.S. Department of Energy's (DOE) Brookhaven National Laboratory and collaborators at Dow AgroSciences report engineering a plant that produces industrially relevant levels of compounds that could potentially be used to make plastics.

Related Articles


The research is reported online in Plant Physiology, and will appear in print in the December issue.

"We've engineered a new metabolic pathway in plants for producing a kind of fatty acid that could be used as a source of precursors to chemical building blocks for making plastics such as polyethylene," said Brookhaven biochemist John Shanklin, who led the research. "The raw materials for most precursors currently come from petroleum or coal-derived synthetic gas. Our new way of providing a feedstock sourced from fatty acids in plant seeds would be renewable and sustainable indefinitely. Additional technology to efficiently convert the plant fatty acids into chemical building blocks is needed, but our research shows that high levels of the appropriate feedstock can be made in plants."

The method builds on Shanklin's longstanding interest in fatty acids -- the building blocks for plant oils -- and the enzymes that control their production. Discovery of the genes that code for the enzymes responsible for so called "unusual" plant oil production encouraged many researchers to explore ways of expressing these genes and producing certain desired oils in various plants.

"There are plants that naturally produce the desired fatty acids, called 'omega-7 fatty acids,' in their seeds -- for example, cat's claw vine and milkweed -- but their yields and growth characteristics are not suitable for commercial production," Shanklin said. Initial attempts to express the relevant genes in more suitable plant species resulted in much lower levels of the desired oils than are produced in plants from which the genes were isolated. "This suggests that other metabolic modifications might be necessary to increase the accumulation of the desired plant seed oils," Shanklin said.

"To overcome the problem of poor accumulation, we performed a series of systematic metabolic engineering experiments to optimize the accumulation of omega-7 fatty acids in transgenic plants," Shanklin said. For these proof-of-principle experiments, the scientists worked with Arabidopsis, a common laboratory plant.

Enzymes that make the unusual fatty acids are variants of enzymes called "desaturases," which remove specific hydrogen atoms from fatty acid chains to form carbon-carbon double bonds, thus desaturating the fatty acid. First the researchers identified naturally occurring variant desaturases with desired specificities, but they worked poorly when introduced into Arabidopsis. They next engineered a laboratory-derived variant of a natural plant enzyme that worked faster and with greater specificity than the natural enzymes, which increased the accumulation of the desired fatty acid from less than 2 percent to around 14 percent.

Though an improvement, that level was still insufficient for industrial-scale production. The scientists then assessed a number of additional modifications to the plant's metabolic pathways. For example, they "down-regulated" genes that compete for the introduced enzyme's fatty acid substrate. They also introduced desaturases capable of intercepting substrate that had escaped the first desaturase enzyme as it progressed through the oil-accumulation pathway. In many of these experiments they observed more of the desired product accumulating. Having tested various traits individually, the scientists then combined the most promising traits into a single new plant.

The result was an accumulation of the desired omega-7 fatty acid at levels of about 71 percent in the best-engineered line of Arabidopsis. This was much higher than the omega-7 fatty acid levels in milkweed, and equivalent to those seen in cat's claw vine. Growth and development of the engineered Arabidopsis plants was unaffected by the genetic modifications and accumulation of omega-7 fatty acid.

"This proof-of-principle experiment is a successful demonstration of a general strategy for metabolically engineering the sustainable production of omega-7 fatty acids as an industrial feedstock source from plants," Shanklin said.

This general approach -- identifying and expressing natural or synthetic enzymes, quantifying incremental improvements resulting from additional genetic/metabolic modifications, and "stacking" of traits -- may also be fruitful for improving production of a wide range of other unusual fatty acids in plant seeds.

This research was funded by the DOE Office Science, and by The Dow Chemical Company and Dow AgroSciences.


Story Source:

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


Journal Reference:

  1. Huu Tam Nguyen, Girish Mishra, Edward Whittle, Scott A. Bevan, Ann Owens Merlo, Terence A. Walsh, and John Shanklin. Metabolic Engineering of Seeds can Achieve Levels of w-7 Fatty Acids Comparable to the Highest Levels Found in Natural Plant Sources. Plant Physiology, December 2010

Cite This Page:

DOE/Brookhaven National Laboratory. "Engineered plants make potential precursor to raw material for plastics." ScienceDaily. ScienceDaily, 9 November 2010. <www.sciencedaily.com/releases/2010/11/101108140638.htm>.
DOE/Brookhaven National Laboratory. (2010, November 9). Engineered plants make potential precursor to raw material for plastics. ScienceDaily. Retrieved April 21, 2015 from www.sciencedaily.com/releases/2010/11/101108140638.htm
DOE/Brookhaven National Laboratory. "Engineered plants make potential precursor to raw material for plastics." ScienceDaily. www.sciencedaily.com/releases/2010/11/101108140638.htm (accessed April 21, 2015).

Share This


More From ScienceDaily



More Plants & Animals News

Tuesday, April 21, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

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
Five Years Later, the BP Oil Spill Is Still Taking Its Toll

Five Years Later, the BP Oil Spill Is Still Taking Its Toll

AFP (Apr. 20, 2015) On April 20, 2010, an explosion and fire on the Deepwater Horizon rig in the Gulf of Mexico started the biggest oil spill in US history. BP recently reported the Gulf is recovering well, but scientists paint a different picture. Duration: 02:36 Video provided by AFP
Powered by NewsLook.com
Thai Customs Seize African Elephant Tusks Worth $6 Mn

Thai Customs Seize African Elephant Tusks Worth $6 Mn

AFP (Apr. 20, 2015) Thai customs seize four tonnes of African elephant ivory worth $6 million at a Bangkok port in a container labelled as beans. Duration: 00:47 Video provided by AFP
Powered by NewsLook.com
Un-Bee-Lievable: Bees on the Loose After Washington Truck Crash

Un-Bee-Lievable: Bees on the Loose After Washington Truck Crash

Reuters - US Online Video (Apr. 17, 2015) A truck carrying honey bees overturns near Lynnwood, Washington, spreading boxes of live bees across the highway. Rough Cut (no reporter narration). 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:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

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