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Blacksburg, Va. - The economics of producing biopharmaceuticals from
transgenic plants such as tobacco is still a roadblock to producing large
quantities of urgently needed medicines, especially for people in
underdeveloped nations, August2004.

Chenming (Mike) Zhang is testing a variety of ways to economically recover
recombinant proteins from transgenic tobacco using different protein
separation techniques.

Zhang, an assistant professor in the Department of Biological Systems
Engineering (BSE) in the College of Engineering at Virginia Tech, is working
with a team of three Ph.D. students to develop transgenic tobacco plants
able to express recombinant proteins economically. Recombinant proteins are
potential therapeutic agents for treating human and animal diseases and
creating new vaccines. Plant-made vaccines are especially beneficial because
plants are free of human diseases, reducing the cost to screen for viruses
and bacterial toxins.

"Recombinant protein production from transgenic plants is challenging, not
just from the molecular biology aspect of creating high expression plant
lines, but also from the engineering aspect of recovering and purifying the
proteins economically -- the importance of which cannot be overlooked,"
Zhang said.

Recombinant proteins are proteins expressed by a host other than their
native hosts. For example, if the gene for human growth hormone is inserted
into the genetic code of yeast (gene recombination), then the corresponding
protein expressed in the yeast is called recombinant human growth hormone.

Zhang's research starts with introducing the genes of interest into tobacco
plants and then developing economical processes for recovering and purifying
the expressed proteins. Relaxin, one of the proteins his team is studying,
could potentially benefit patients with asthma, hay fever, and even
cardiovascular disease.

Because most recombinant proteins are for therapeutic uses, they need to be
highly purified to be safe for human use. Thus, once a protein is expressed,
whether by transgenic tobacco or bacteria, the protein first needs to be
recovered into liquid solutions before purification.

"Because of the high purity required, the purification is rigorous and not
surprisingly, very expensive. Therefore, development of more economical
techniques for protein purification is always an engineering challenge in
order to lower the cost of therapeutic proteins or biopharmaceuticals,"
Zhang said.

Zhang uses tobacco in his research because it is a non-food crop and is well
suited as a "factory" for recombinant protein production. The leafy green
tobacco plant is relatively easy to alter genetically and produces thousands
of seeds and a great deal of biomass. As a non-food crop, genetically
manipulated tobacco will not pose a safety threat to products consumed by
humans. "Since tobacco is neither a food nor a feed-crop, transgenic tobacco
will not enter our food chain," Zhang said.

The research is funded by the Jeffress Memorial Trust and the Tobacco
Initiative.

Zhang is the director of both the Protein Separation Laboratory and the Unit
Operations Laboratory at Virginia Tech. The Protein Separation Laboratory
supports research in protein expression and purification process development
from transgenic plants and other expression systems. The Unit Operations
Laboratory supports a course by the same name taught by Zhang in biological
systems engineering. He is also affiliated with the Virginia Tech-Wake
Forest University School of Biomedical Engineering and Sciences.

The College of Engineering Dean's Award for Outstanding Assistant Professor
was presented to Zhang in 2004. His nomination was based on his
extraordinary level of activities and accomplishments in curriculum
development and teaching, development of a viable research program, and his
cooperative efforts with colleagues at Virginia Tech and around the nation.

Before coming to Virginia Tech in 2001, Zhang was a research and development
scientist for two years at Covance Biotechnology Services (now Diosynth RTP)
in Cary, N. C.

Zhang received his bachelor's and master's degrees in metallurgical physical
chemistry from the University of Science and Technology in Beijing, China,
in 1986 and 1991, respectively. He received a second master's degree in
physical and analytical chemistry in 1996 from Iowa State University as well
as his Ph.D. in chemical engineering in 1999.

The College of Engineering at Virginia Tech is internationally recognized
for its excellence in 14 engineering disciplines and computer science. The
college's 5,600 undergraduates benefit from an innovative curriculum that
provides a "hands-on, minds-on" approach to engineering education,
complementing classroom instruction with two unique design-and-build
facilities and a strong Cooperative Education Program. With more than 50
research centers and numerous laboratories, the college offers its 2,000
graduate students opportunities in advanced fields of study such as
biomedical engineering, state-of-the-art microelectronics, and
nanotechnology.

Learn more about Dr. Zhang at
[www.bse.vt.edu] Or
[www.sbes.vt.edu]

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