Petrochemicals are found in thousands of everyday
products, from clothing to food preservatives to plastics. Imagine if many of
those chemicals could be made without petroleum and instead with biological
processes. Using the tools of synthetic biology scientists at the United States
Department of Energy’s Joint BioEnergy Institute (JBEI) have done just that,
and now a startup company has been formed to commercialize the technology.
Lygos is the first company to spin out of JBEI, a
Department of Energy research center established in 2007 to pursue
breakthroughs in the production of cellulosic biofuels. The five company cofounders
include Jay Keasling, director of JBEI and a world authority on synthetic
biology and metabolic engineering who holds joint appointments with the
Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of
California (UC) Berkeley.
The process uses sugar as a feedstock, which is
metabolized by designer microorganisms to yield any of a number of molecules. “This is the future of chemical manufacturing,” said Lygos CEO Jeffrey (Clem)
Fortman, one of the company cofounders and also a JBEI researcher. “Oil is
becoming expensive, and at some point it will be depleted. Sugar is getting
more expensive, but it’s still lagging way behind oil.”
The Lygos technology repurposes a class of proteins
that have been used for decades to make antibiotics and other drugs. Polyketide
synthases (PKS) are a family of multifunctional enzymes that produce
polyketides, hydrocarbon chains that serve as a backbone for many widely used
natural and synthetic organic chemicals. The JBEI researchers redesigned the PKS
process, or pathway, by mixing and matching genetic information to produce
compounds that were never made by nature but have become the ubiquitous
synthetic materials of our everyday lives.
The method can produce compounds such as nylon
precursors, polyester components, styrene, and propylene. The latter two are
widely used in plastics and countless consumer products. Besides producing
products currently made with petroleum, the Lygos technology can also be used
to engineer products with characteristics that have never been achieved before,
or that have been too expensive to produce otherwise. Biofuels are another
possible product.
Although other companies are using biological
processes to make certain compounds, what’s superior about Lygos’ technology is
that it is a platform as well as a process, theoretically allowing for a huge
number of molecules. PKS are composed of discrete modules, each catalyzing the
chain growth of a single step. Synthesis of a desired compound can be
programmed by selection and genetic manipulation of PKS.
“It’s a broad array of things we can make;
estimates are in the tens of thousands, or even higher, of different molecules
we could potentially make,” said Fortman. “However the mass market compounds
are far fewer than that.”
The company has achieved production of a number of
petrochemical replacements at laboratory scale. It is currently optimizing the
production of its first target compounds.
Removing petroleum from chemical manufacturing
would remove the risk of producing the level of greenhouse gases, hazardous
waste, and environmental pollution that is associated with production of
petrochemicals. The Lygos process is nonpolluting and promises to be nearly
carbon neutral. Although bioprocesses do generate carbon dioxide, because more
feedstock is planted—in this case, sugar—atmospheric carbon dioxide is captured
by the plants. By contrast, in the case of petrochemicals, hydrocarbons are
pulled from the ground and emit carbon dioxide when combusted.
The other three company cofounders are Leonard
Katz, Eric Steen, and Jeffrey Dietrich.
