In the parallel universe of the microbiological world, there is a current superstar species of blue-green algae that, through its powers of photosynthesis and carbon dioxide fixation, or uptake, can produce (count 'em) ethanol, hydrogen, butanol, isobutanol and potentially biodiesel. Now that's some five-tool player.
In baseball, you call that player Willie Mays or Mike Trout. In microbiology, it goes by Synechocystis 6803, a versatile, specialized bacterium known as a cyanobacterium. It makes pikers out of plants when it comes to capturing and storing energy from photosynthesis, and it's a natural in converting the greenhouse gas carbon dioxide (CO2) to useful chemicals that could help both tame global warming and sustain energy supply.
In addition, genetically engineered Synechocystis 6803 also has the potential to make commodity chemicals and pharmaceuticals.
Granted, that's mostly in laboratories, on the liter scale. Because of its versatility and potential, this microscopic organism is one of the most studied of its kind since it was discovered in 1968. But just as in baseball, where "can't miss" five-tool prospects are signed yearly with great expectations and never achieve their promise, Synechocystis 6803 has yet to deliver.
Fuzhong Zhang, PhD, assistant professor of energy, environmental & chemical engineering at Washington University in St. Louis, works with Synechocystis 6803 — as well as other microbes and systems — in the areas of synthetic biology, protein engineering and metabolic engineering, with special focus on synthetic control systems to make the organism reach its untapped prowess.
Zhang says the biotech world has to overcome several challenges to put the engineered microbes in the applications stage. Zhang will be in the thick of them.
"My goal is to engineer microbes and turn them into microfactories that produce useful chemicals," Zhang says. "Synechocystis is particularly interesting because it can use CO2 as the only carbon source. Engineering this bacterium would turn the fixed CO2 into metabolites that can be further converted to fuels and other chemicals through designed biosynthetic pathways."
Traditional chemical production requires high pressure and temperatures and literally tons of chemical solvents, but the microbial approach is very eco-friendly: Once the engineered cyanobacteria start to grow, all they need are water, basic salts and the CO2.
In an academic "scouting report" of Synechocystis, published in the August 2013 Marine Drugs, Zhang and colleagues summarize recent research and conclude that production speed has to be increased and new genetic tools must be developed to control the biochemistry inside Synechocystis so that chemical productivities will be improved to make this technology economically viable.
Current industry specifications for potentially scalable chemical production are roughly 100 grams per liter of fuel or chemicals. Presently, the laboratory production is generally less than 1 gram per liter, and the efficiency is very low.
Zhang says the research community needs better tools to control gene expression. For example, promoters — little stretches of DNA before genes of interest that help control gene expression — with predictable strength are needed. They also need better cellular biosensors that can sense key metabolites and control the production of vital proteins that create the desired chemicals.
And they need to engineer the organisms' circadian rhythms (day/night) to someday produce organisms that work around the clock making a fuel or chemical. Natural Synechocystis 6803, for instance, performs a yeoman's task of producing and storing energy molecules during the day through photosynthesis, but at night, it uses a different set of metabolisms to consume the stored energy.
The natural circadian rhythm has to be rewired to make a biofuel 24 hours a day.
Zhang's research includes developing gene expression tools, new chemical biosynthetic pathways and circadian control tools for cyanobacteria.
"I'm confident that in two or three years we will have more potent tools to engineer gene expression levels and timing, which will speed up the process more accurately and efficiently," he says.
Also, his group has been working to develop dynamical control systems in microbes that function like meters and valves in a traditional chemical production plant – the meters calculate pressure and flow, and the valves control them.
"It's a biological version of the valve-and-meter model to control the flow of metabolites that make the production of fuel and chemicals more efficiently," he says.
Yu Y, You L, Liu D, Hollinshead W, Tang Y, Zhang F. Development of Synechocystis sp. PCC 6803 as a Phototrophic Cell Factory. Marine Drugs 2013, 11, 2894-2916; doi: 10.3390/nd11082894.
Funding for this research was provided by the National Science Foundation.
The School of Engineering & Applied Science at Washington University in St. Louis focuses intellectual efforts through a new convergence paradigm and builds on strengths, particularly as applied to medicine and health, energy and environment, entrepreneurship and security. With 82 tenured/tenure-track and 40 additional full-time faculty, 1,300 undergraduate students, 700 graduate students and more than 23,000 alumni, we are working to leverage our partnerships with academic and industry partners — across disciplines and across the world — to contribute to solving the greatest global challenges of the 21st century.
Neil Schoenherr | EurekAlert!
The irresistible fragrance of dying vinegar flies
16.08.2017 | Max-Planck-Institut für chemische Ökologie
How protein islands form
15.08.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
Researchers from the University of Miami (UM) Rosenstiel School of Marine and Atmospheric Science, the Italian Space Agency (ASI), and the Instituto Geofisico--Escuela Politecnica Nacional (IGEPN) of Ecuador, showed an increasing volcanic danger on Cotopaxi in Ecuador using a powerful technique known as Interferometric Synthetic Aperture Radar (InSAR).
The Andes region in which Cotopaxi volcano is located is known to contain some of the world's most serious volcanic hazard. A mid- to large-size eruption has...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
16.08.2017 | Physics and Astronomy
16.08.2017 | Materials Sciences
16.08.2017 | Interdisciplinary Research