Nav: Home

Survival of the hardest working

March 21, 2016

A team of engineers at Washington University in St. Louis discovered a way to improve production of biofuels, pharmaceuticals, materials and other useful chemicals by capitalizing on the work ethic of cells.

The research team, led by Fuzhong Zhang, assistant professor of energy, environmental & chemical engineering in the School of Engineering & Applied Science, discovered that genetically identical microbial cells have different work ethics. The team developed a tool to ensure that the hard-working cells keep working hard and the low-performing cells are eliminated.

The research is published online in Nature Chemical Biology March 21.

When engineering microbes to produce useful chemicals, cells from the same ancestor often perform tasks differently. Using engineered strains of the bacteria E. coli, Zhang's team demonstrated that only a small fraction of cells worked hard to produce the desired chemicals, while the majority of others were content to not work, but to eat nutrients intended for working cells. The different work ethic is not caused by unintended genetic mutations, they found, but rather by "noise" in biology, which is inherent in nature and impossible to eliminate.

To prevent the lazy cells from wasting nutrients, Zhang's team developed a quality-control tool, called PopQC, that can keep the hard-working, high-performing cells working while eliminating the low-performing cells. The team placed a sensor inside the cells that could sense how much work each cell was doing. If the sensor determined that a cell was making a lot of the products, the sensor would trigger a controller to make a protein that allowed the cells to survive and grow. If the sensor determined that the cell was not working hard enough, it remained silent, and the lazy cells died from lack of nutrition or were knocked out by antibiotics.

The team applied PopQC to two engineered strains of E. coli: one designed to produce free fatty acid, a precursor for biofuels or other high-volume chemicals; and one designed to produce tyrosine, an amino acid that can be a precursor to pharmaceuticals. PopQC allowed the hard-working cells to dominate in both cultures and led to threefold enhanced ensemble production of both free fatty acid and tyrosine, Zhang said.

"PopQC could be applied to a variety of biosynthetic pathways and host organisms as long as a proper sensor exists that detects the product in the engineered host," Zhang said. "Because noise is a universal problem in biology, the design principle of this work should inspire engineers from many other fields to improve efficiency of engineered systems."

Zhang has filed a patent application for the design principle with assistance from the university's Office of Technology Management.

Zhang's research interests focus on applying synthetic biology methodologies to develop microbial systems for the sustainable production of biofuels, chemicals and materials with defined structures and controllable properties. He also is interested in developing tools that allow engineered microbes to synthesize target products and to perform complex tasks more efficiently and robustly.
-end-


Washington University in St. Louis

Related Biofuels Articles:

Cellulosic biofuels can benefit the environment if managed correctly
Could cellulosic biofuels -- or liquid energy derived from grasses and wood -- become a green fuel of the future, providing an environmentally sustainable way of meeting energy needs?
Solving a sweet problem for renewable biofuels and chemicals
Reed Cartwright and Xuan Wang have teamed up to try to break through the innovation bottleneck for the renewable bioproduction of fuels and chemicals.
Making oil from algae -- towards more efficient biofuels
The mechanism behind oil synthesis within microalgae cells has been revealed by a Japanese research team.
WSU study finds people willing to pay more for new biofuels
When it comes to second generation biofuels, Washington State University research shows that consumers are willing to pay a premium of approximately 11 percent over conventional fuel.
'Super yeast' has the power to improve economics of biofuels
Scientists at the University of Wisconsin-Madison and the Great Lakes Bioenergy Research Center have found a way to nearly double the efficiency with which a commonly used industrial yeast strain converts plant sugars to biofuel.
More Biofuels News and Biofuels Current Events

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Anthropomorphic
Do animals grieve? Do they have language or consciousness? For a long time, scientists resisted the urge to look for human qualities in animals. This hour, TED speakers explore how that is changing. Guests include biological anthropologist Barbara King, dolphin researcher Denise Herzing, primatologist Frans de Waal, and ecologist Carl Safina.
Now Playing: Science for the People

#534 Bacteria are Coming for Your OJ
What makes breakfast, breakfast? Well, according to every movie and TV show we've ever seen, a big glass of orange juice is basically required. But our morning grapefruit might be in danger. Why? Citrus greening, a bacteria carried by a bug, has infected 90% of the citrus groves in Florida. It's coming for your OJ. We'll talk with University of Maryland plant virologist Anne Simon about ways to stop the citrus killer, and with science writer and journalist Maryn McKenna about why throwing antibiotics at the problem is probably not the solution. Related links: A Review of the Citrus Greening...