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Greg Rorrer
Associate Professor, Chemical Engineering
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RESEARCH:
Our laboratory conducts research on the chemical engineering aspects of emerging bioprocess technologies. We are currently developing bioreactors for plant cell culture and marine plant cell culture. We are also exploring the feasibility of using biopolymer beads for various biotechnological and waste-water treatment applications.
Plant Cell Culture. Plant cells in liquid suspension culture can make valuable pharmaceutical compounds through a variety of biosynthetic pathways. Usually, significant levels of secondary metabolites are expressed only at very high cell density near the end of the growth phase. The large-scale cultivation of plant cells in stirred tank or airlift bioreactors at the high cell densities required for secondary product release is not easy: nonuniform mixing, shear damage of fragile plant cells, and poor oxygen transfer are barriers to process development. In our laboratory, we are studying the fundamentals of mixing and mass transfer in dense culture using two experimental techniques. The first experiment measures oxygen mass transport in stirred-tank cultures of tobacco cells. The second experiment quantifies the effects of mixing parameters (stirrer speed, aeration rate) on cell viability and secondary metabolite productivity.
Marine Plant Cell Culture. Marine plants can also produce valued biomedicinal compounds. In collaboration with the College of Pharmacy, we are working to establish cell suspension cultures of red and brown macroalagal plants which synthesize bioactive compounds of the arachidonic acid cascade. We are also developing bioreactors for controlled cultivation of marine plant cells and biosynthesis of medicinals.
Porous Biopolymer Beads. Chitosan is a glucosamine polymer derived form chitin, the main component of crustacean shells. Recently, our laboratory has developed a process to make highly porous, magnetic beads of cross-linked chitosan. We are exploring two applications for these porous biopolymer beads. First, since chitosan has a high affinity for heavy metal ions, we are evaluating the technical feasibility of removing heavy metals from aqueous waste water streams using porous, magnetic chitosan beads in a magnetically-stabilized bed process. Second, we are considering the porous chitosan bead as a support for cell immobilization.