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Biotechnology
Polymer potential
Bioplastics may be the buzzword for today’s graduates
"I want to say one word to you.
Just one word... Plastics”
Friedrich Srienc is developing versatile and
affordable bio-based plastics.
When Dustin Hoffman’s character,
Benjamin Braddock, received that
famous career tip in the 1967 movie
The Graduate, the world of petroleum-
based plastics was in its heyday.
“Space-age” plastics turned up
in everything from automobiles to
shiny vinyl clothing. Now, in a world
of diminishing oil
reserves and burgeoning
plastics
that don’t decompose,
biologically derived
polymers
hold even greater
promise.
Yet, for the bioplastics
industry to thrive, it must
overcome two obstacles: cost and
versatility. If bioplastics cost more
than their petroleum-based counterparts,
no one will use them,
even if they’re better for the environment.
And these new bioplastics
must offer an array of properties—
strength, pliability, transparency,
and formability, for
example—to match petro-plastics.
Some bio-based polymers are
already on the market. Cargill
Dow’s NatureWorks products, for
example, are used in packaging,
blankets, and wipes. Cargill Dow
turns unrefined dextrose from corn
into lactic acid from which a polymer
is formed. These types of plastics
have their limitations, however,
such as intolerance to heat.
In contrast, polyhydroxyalkanoates
(PHAs), a family of biodegradable
polymers naturally synthesized by
bacteria as carbon and energy
reserve materials, offers promise.
Friedrich Srienc, a native of
Austria who came to the
University of Minnesota in 1985,
works with PHAs. He and a cadre
of other researchers in the
Biotechnology Institute are tackling
the issues of cost and versatility
in biopolymer production.
They have received IREE grants
for two major projects.
The first is a
$270,000 threeyear
grant with
which Srienc and
Romas Kazlauskas,
an associate
professor in the
Department of
Biochemistry,
Molecular Biology and Biophysics,
seek to develop new yeast strains
capable of synthesizing polymers
under anaerobic conditions.
Anaerobic (in absence of oxygen)
processing requires less energy,
which reduces the cost. Srienc
maintains that coupling PHA production
with ethanol production
(using the same biological raw
materials) will improve the economic
viability of both biopolymer
and ethanol production.
The second is a three-year,
$429,000 grant funding work in
which Srienc is collaborating with
Kazlauskas and Claudia Schmidt-
Dannert, associate professor in the
Department of Biochemistry,
Molecular Biology, and Biophysics.
Combining their expertise in
enzyme-catalyzed synthesis,
biosynthetic pathway engineering,
and metabolic network engineering,
they are working to develop a new
class of polymers with electrical
conducting properties, or electronic
plastics. Such plastics are currently
synthesized from petroleum and
are used in lasers, ultra-fast image
processors, thin-film transistors,
highly sensitive plastic photodiodes,
and integrated circuits.
So, Benjamin Braddock might
receive the same advice today as
he did in the ’60s. But if Srienc and
company achieve their goals, the
word will be... bioplastics.
—Terri Peterson Smith
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