(425e) Production of Recombinant Human Gelatin in Rice Cell Cultures

Bovine-derived gelatin is used extensively in the manufacturing of pharmaceutical capsules, however the intrinsic variability and safety concerns have prompted the development of recombinant production technologies. Transgenic plants can provide an attractive technology for the production of low cost/high volume industrial proteins such as gelatin. We are developing plant cell culture as a complementary technology to transgenic plants for the fast evaluation of plant-derived industrial recombinant proteins. Stably transformed rice cell lines were generated containing a plant codon optimized gene coding for a fragment of human a(1)-I collagen (100kDa rGelatin) and a rice a-amylase secretion signal peptide under the control of a constitutive maize ubiquitin promoter. Transgenic rice cell cultures were scaled up for production in a 3L bioreactor culture. The maximum extracellular gelatin concentration, as measured by ELISA, was 170 mg/L at 11 days, corresponding to 0.5% of the total extracellular protein. The rGelatin was positively identified by immunoblot following SDS PAGE. Future work will focus on improving bioreactor productivity, improving product quality, and introducing human-like proline hydroxylation of rGelatin through metabolic engineering of the rice cell host.