Corporate Banner
Satellite Banner
Technology
Networks
Scientific Communities
 
Become a Member | Sign in
Home>News>This Article
  News
Return

Engineering Cells for more Efficient Biofuel Production

Published: Tuesday, February 19, 2013
Last Updated: Tuesday, February 19, 2013
Bookmark and Share
Yeast research takes a step toward production of alternatives to gasoline.

In the search for renewable alternatives to gasoline, heavy alcohols such as isobutanol are promising candidates. Not only do they contain more energy than ethanol, but they are also more compatible with existing gasoline-based infrastructure. For isobutanol to become practical, however, scientists need a way to reliably produce huge quantities of it from renewable sources.

MIT chemical engineers and biologists have now devised a way to dramatically boost isobutanol production in yeast, which naturally make it in small amounts. They engineered yeast so that isobutanol synthesis takes place entirely within mitochondria, cell structures that generate energy and also host many biosynthetic pathways. Using this approach, they were able to boost isobutanol production by about 260 percent.

Though still short of the scale needed for industrial production, the advance suggests that this is a promising approach to engineering not only isobutanol but other useful chemicals as well, says Gregory Stephanopoulos, an MIT professor of chemical engineering and one of the senior authors of a paper describing the work in the Feb. 17 online edition of Nature Biotechnology.

“It’s not specific to isobutanol,” Stephanopoulos says. “It’s opening up the opportunity to make a lot of biochemicals inside an organelle that may be much better suited for this purpose compared to the cytosol of the yeast cells.”

Stephanopoulos collaborated with Gerald Fink, an MIT professor of biology and member of the Whitehead Institute, on this research. The lead author of the paper is Jose Avalos, a postdoc at the Whitehead Institute and MIT.

Historically, researchers have tried to decrease isobutanol production in yeast, because it can ruin the flavor of wine and beer. However, “now there’s been a push to try to make it for fuel and other chemical purposes,” says Avalos, the paper’s lead author.

Yeast typically produce isobutanol in a series of reactions that take place in two different cell locations. The synthesis begins with pyruvate, a plentiful molecule generated by the breakdown of sugars such as glucose. Pyruvate is transported into the mitochondria, where it can enter many different metabolic pathways, including one that results in production of valine, an amino acid. Alpha-ketoisovalerate (alpha-KIV), a precursor in the valine and isobutanol biosynthetic pathways, is made in the mitochondria in the first phase of isobutanol production.

Valine and alpha-KIV can be transported out to the cytoplasm, where they are converted by a set of enzymes into isobutanol. Other researchers have tried to express all the enzymes needed for isobutanol biosynthesis in the cytoplasm. However, it’s difficult to get some of those enzymes to function in the cytoplasm as well as they do in the mitochondria.  

The MIT researchers took the opposite approach: They moved the second phase, which naturally occurs in the cytoplasm, into the mitochondria. They achieved this by engineering the metabolic pathway’s enzymes to express a tag normally found on a mitochondrial protein, directing the cell to send them into the mitochondria.

This enzyme relocation boosted the production of isobutanol by 260 percent, and yields of two related alcohols, isopentanol and 2-methyl-1-butanol, went up even more — 370 and 500 percent, respectively.

There are likely several explanations for the dramatic increase, the researchers say. One strong possibility, though difficult to prove experimentally, is that clustering the enzymes together makes it more likely that the reactions will occur, Avalos says.

Another possible explanation is that moving the second half of the pathway into the mitochondria makes it easier for the enzymes to snatch up the limited supply of precursors before they can enter another metabolic pathway.

“Enzymes from the second phase, which are naturally out here in the cytoplasm, have to wait to see what comes out of the mitochondria and try to transform that. But when you bring them into the mitochondria, they’re better at competing with the pathways in there,” Avalos says.

The findings could have many applications in metabolic engineering. There are many situations where it could be advantageous to confine all of the steps of a reaction in a small space, which may not only boost efficiency but also prevent harmful intermediates from drifting away and damaging the cell.

The researchers are now trying to further boost isobutanol yields and reduce production of ethanol, which is still the major product of sugar breakdown in yeast.

“Knocking out the ethanol pathway is an important step in making this yeast suitable for production of isobutanol,” Stephanopoulos says. “Then we need to introduce isobutanol synthesis, replacing one with the other, to maintain everything balanced within the cell.”


Further Information

Join For Free

Access to this exclusive content is for Technology Networks Premium members only.

Join Technology Networks Premium for free access to:

  • Exclusive articles
  • Presentations from international conferences
  • Over 3,200+ scientific posters on ePosters
  • More Than 4,800+ scientific videos on LabTube
  • 35 community eNewsletters


Sign In



Forgotten your details? Click Here
If you are not a member you can join here

*Please note: By logging into TechnologyNetworks.com you agree to accept the use of cookies. To find out more about the cookies we use and how to delete them, see our privacy policy.

Related Content

New Device can Study Electric Field Cancer Therapy
Microfluidic device allows study of electric field cancer therapy through low-intensity fields, preventing malignant cells spreading.
Friday, July 08, 2016
Programmable RNA Vaccines
Tests in mice show the vaccines work against Ebola, influenza, and a common parasite.
Wednesday, July 06, 2016
Seeing RNA at the Nanoscale
MIT researchers have developed a new way to image proteins and RNA inside neurons of brain tissue.
Wednesday, July 06, 2016
Tough New Hydrogel Hybrid Doesn’t Dry Out
Water-based material could be used to make artificial skin, longer-lasting contact lenses.
Friday, July 01, 2016
Wireless, Wearable Toxic-Gas Detector
Inexpensive sensors could be worn by soldiers to detect hazardous chemical agents.
Friday, July 01, 2016
New System for Detecting Explosives
Spectroscopic system with chip-scale lasers cuts detection time from minutes to microseconds.
Wednesday, June 01, 2016
Illuminating Hidden Gene Regulators
New super-resolution technique visualizes important role of short-lived enzyme clusters.
Friday, May 27, 2016
Controlling RNA in Living Cells
Modular, programmable proteins can be used to track or manipulate gene expression.
Wednesday, April 27, 2016
Long-Term Drug Release
New tablet attaches to the lining of the GI tract, resists being pulled away.
Thursday, April 07, 2016
Pharmacy on Demand
New, portable system can be configured to produce different drugs.
Monday, April 04, 2016
A Programming Language for Living Cells
New language lets researchers design novel biological circuits.
Monday, April 04, 2016
Why Some Tumors Withstand Treatment
Mechanism uncovered that allows cancer cells to evade targeted therapies.
Thursday, March 17, 2016
Cancer Cells Remodel Environments Before Spreading
Researchers at MIT have found that the cancer cells remodel their environment to make it easier to reach nearby blood vessels.
Wednesday, March 16, 2016
Paving the Way for Metastasis
Cancer cells remodel their environment to make it easier to reach nearby blood vessels.
Tuesday, March 15, 2016
A New Way to Discover DNA Modifications
Researchers systematically find molecules that help regulate and protect DNA.
Wednesday, March 02, 2016
Scientific News
Liquid Biopsies: Miracle Diagnostic or Next New Fad?
Thanks to the development of highly specific gene-amplification and sequencing technologies liquid biopsies access more biomarkers relevant to more cancers than ever before.
Connectome Map More Than Doubles Human Cortex’s Known Regions
Researchers at NIH have developed software that automatically detects the “fingerprint” of each of these areas in an individual’s brain scans.
Discovered Through ‘Big Data’ Analysis
Researchers at the SBP have identified over 100 new genetic regions that affect the immune response to cancer.
Human Stem Cells to Rapidly Generate Bone, Heart Muscle
A new study shows that combining positive and negative signals can quickly and efficiently steer stem cells down complex developmental pathways to become specialized tissues that could be used in the clinic.
New Mechanism of Tuberculosis Infection
Researchers at UTSW Medical Center have identified a new way that tuberculosis bacteria get into the body, revealing a potential therapeutic angle to explore.
New Therapeutic Targets For Small Cell Lung Cancer Identified
Researchers at UTSW Medical Center have identified a protein termed ASCL1 that is essential to the development of small cell lung cancer and that, when deleted in the lungs of mice, prevents the cancer from forming.
Eliminating Doubt in Criminal Investigations
New ASU certificate to help curb error, misunderstanding in the quest for justice.
Determination of 13 Organic Toxicants in Human Blood
Researchers have utilised liquid-liquid extraction coupling HPLC-MS/MS to identify and quantify organic toxicants in human blood.
A Novel Cell Culture Model For Forensic Biology Experiments
Researchers have developed a new cell culture model which provides an efficient research tool in forensic biology.
Rhino DNA Bank Aids Anti-Poaching Fight
At the University of Pretoria's Veterinary Genetics Laboratory (VGL) at Onderstepoort, Dr Cindy Harper and her team have developed a ground-breaking technique to collect and catalogue DNA from rhinos and rhino horns.
Scroll Up
Scroll Down
Skyscraper Banner

Skyscraper Banner
Go to LabTube
Go to eposters
 
Access to the latest scientific news
Exclusive articles
Upload and share your posters on ePosters
Latest presentations and webinars
View a library of 1,800+ scientific and medical posters
3,200+ scientific and medical posters
A library of 2,500+ scientific videos on LabTube
4,800+ scientific videos
Close
Premium CrownJOIN TECHNOLOGY NETWORKS PREMIUM FOR FREE!