By Susan Gaidos
Scientists are reporting an advance toward turning corn plants into
natural factories for producing gelatin to replace animal-sourced gelatin
widely used by the pharmaceutical industry for manufacturing capsules and
tablets. The advance, described today at the 234th national meeting of the
American Chemical Society, may lead to a safe, inexpensive source of this
protein for manufacturers who now rely on material obtained as a by-product
of meat production.
Today, production of gelatin, a jelly-like substance, relies on the
same fundamental methodology employed since commercial production began in
the 17th century: Gelatin is derived from the break-down of collagen, which
is a component of skin, tendon, bone, cartilage and connective tissue of
animals. While there are no naturally occurring plant sources of gelatin,
scientists have successfully modified plants, such as corn, to have a gene
that results in the production of ?recombinant? gelatin.

About 55,000 tons of animal-sourced gelatin are used every year to
produce capsules and tablets for medicinal purposes. Plant-derived
recombinant gelatin would address concerns about the possible presence of
infectious agents in animal by-products and the lack of traceability of the
source of the raw materials currently used to make gelatin. However, finding
ways to recover and purify recombinant gelatin from plants has remained a
challenge because only very low levels accumulate at the early stages of the
development process.

Now, scientists at Iowa State University in Ames and FibroGen, Inc.,
in South San Francisco say they have developed a purification process to
recover these small quantities of recombinant gelatin present in the early
generations of transgenic corn. The method uses a four-step recovery system
to separate the recombinant protein from other corn proteins with sufficient
purity that its structure and composition can be verified, says Charles
Glatz, Ph.D., a chemical engineer at Iowa State University who directed the
work.

?Protein production from transgenic plants is a challenging process,
with potential pitfalls all along the way,? Glatz says. ?It is important to
develop methods in the early stages of the development program to purify
gelatin to demonstrate that it can be produced properly.?

The studies establish transgenic corn as a viable way to produce
gelatin and potentially other products, Glatz says. In time, researchers may
also be able to develop a variety of ?designer? gelatins, with specific
molecular weights and properties tailored to suit various needs of products
containing gelatin.

?Corn is an ideal production unit, because it can handle high volumes
at a low cost,? he says. In addition the recombinant gelatin is free from
the safety concerns of using meat byproducts.

The purification process relies on chromatographic and filtration
techniques, building upon methods developed by FibroGen to recover
recombinant gelatin produced in yeast.

Glatz says ultrafiltration allowed the group to take advantage of the
size difference between the recombinant protein and other corn proteins.

?This step greatly reduced the process volume for later
chromatographic steps, and was crucial to achieving a high purification
factor.?

The group is now working to refine the method and boost the overall
recombinant protein yields in corn, he says. Though the procedure requires
more testing, Glatz says the technique could someday be used to produce
high-grade gelatin in a safe and inexpensive manner.

Overall costs could be further reduced by combining the production of
gelatin in corn with the extraction of non-protein parts of the grain ? such
as oils and starches ? that are now grown and harvested for biodiesel and
ethanol production, he adds.

?Corn wouldn?t be planted for its gelatin alone, but those products
could help off-set the cost of biorefineries that use corn to produce other
products,? he says.

Cheng Zhang, a doctoral student at Iowa State University, presented
details of the new purification process at the American Chemical Society
meeting.

The American Chemical Society is a nonprofit organization chartered by
the U.S. Congress and a global leader in providing access to
chemistry-related research through its multiple databases, peer-reviewed
journals and scientific conferences. Its main offices are in Washington,
D.C., and Columbus, Ohio.

Note for reporters? use only: For full information about the Boston
meeting, including access to abstracts of more than 9,500 scientific papers
and hundreds of non-technical summaries, visit
[www.acspresscenter.org]. News release images are available at
[chemistry.org].