Bioeconomy Institute

The primary long-term goal of this proposed program is to establish strategies whereby expression of recombinant proteins can best be targeted to simplify downstream processing by making proper matches of the native protein matrix, the extraction method, the separation method, and the characteristics of the recombinant protein. Rapid advances are being made in using plants as hosts for protein expression, especially for producing therapeutic proteins useful in either preventing or treating human and animal diseases and to produce industrially important enzymes. This project focuses on developing optimum strategies and new technologies to recover and purify recombinant proteins from plants, especially for corn.

Processing steps often represent over one-half of the production cost for recombinant proteins. However, it is still possible to consider integrating expression and purification such that the overall cost can be reduced. Today, when most recombinant proteins are recovered from transgenic, one merely takes the entire corn grain, grinds it and extracts it with buffered water to extract water-soluble proteins even though the target protein is expressed in only one of several possible tissues, the germ, the endosperm or the bran. This is highly inefficient because other water-soluble proteins that primarily reside in the germ, the corn embryo, must be removed from the target protein and oil also present in the germ fouls purification equipment such as chromatography columns. Extremely high purity is required for medicinal purposes. It is possible to target expression in one of these tissues to facilitate easier recovery and purification. Additionally, the risk of contaminating commodity corn can be greatly reduced provided an on-farm method of fractionating the corn into its major fractions can be developed. In this way, no viable grain leaves the farmer's field, and shipping and processing mass is reduced. The findings of this research will be used to support industrial clients using a new Biologics Facility (protein extraction) located in the Iowa State University Research Park.

Principal Investigators:

Lawrence A. Johnson, Iowa State University

Charles E. Glatz, Iowa State University

Kan Wang, Iowa State University

M. Paul Scott, USDA-ARS, MWA

Associated Contracts or Grants:

Processing Transgenic Maize to Recover Valuable Therapeutic Proteins and Industrial Enzymes, Ames Laboratory Biorenewable Resources Consortium.
Plant Biotechnology – Iowa: Technologies to Recover Recombinant Proteins from Plants for Use as Therapeutics and Industrial Enzymes.
Biotechnology Test Production: Technologies to Purify Recombinant Proteins from Plants for Use as Therapeutics and Industrial Enzymes.

Participating and/or Sponsoring Organizations:

United States Department of Agriculture (USDA)
United States Department of Energy (DOE)
IA Agriculture and Home Economics Experiment Station (IAHEES)
Meristem Therapeutics, Clarmont-Farrand, France
ProdiGene, College Station, TX
ExSeed genetics, L.L.C., Ames, IA