The market for biologically-derived proteins is said to reach US$300 billion
in the future. Currently, industrial enzymes and other proteins are made in
large, expensive fermenting reactors, but using plants to produce them could
reduce production costs by three times.
Researchers at Cornell University and the University of Illinois have
engineered plants which can produce proteins not native to the plant itself.
The research team genetically modified tobacco plants to produce the
cellulase protein Cel6A, an enzyme. Tobacco is a heavily studied model plant
because so much is known about it. Cel6A belongs to a large group of related
enzymes used in many applications, including modern laundry detergents,
fabric softener, and in food and animal feed.
Genetic engineering was used to deliver DNA with instructions for making the
desired protein into the chloroplasts of plants cells. The plants that
adopted this DNA were then cultivated. Chloroplasts are the
photosynthesizing organelles in plants and contain their own DNA. Plant
cells cannot make their own chloroplasts but inherit them from each daughter
cell during cell division.
"One of the advantages of the technology that we're using is that the
chloroplasts in most crop plants are inherited through the maternal line, so
the genes are not in the pollen," said Beth Ahner, professor of biological
and environmental engineering at Cornell University.