Plant cell cultures are a potential source of important secondary metabolites such as medicinals. Currently, low productivities have impeded commercialization of a broader range of target compounds. Cell immobilization coupled with continuous removal of secreted products has been advocated as a method of enhancing volumetric productivities. Recent advances suggest that the prerequisite of product secretion can be met in a broad range of plant systems. However, the promise of immobilization as a method to increase volumetric productivity has remained unfulfilled, even in cases where the prerequisites have been met. Failures may be traced to design of the biocatalyst particle. Researchers will utilize a combined engineering and biological approach to separate and independently study the effects of immobilization on cell performance. This information will allow comprehensive and rational biocatalyst particle design with respect to: (1) choice of immobilizing matrix; (2) particle physical dimensions; and (3) imposed level of cellular association.The potential commercial application as described by the awardee: This research will directly lead to a commercial process for the production of the rare and important anticancer drug taxol by tissue cultures of 7axi4s Sp. This research will be applicable to other commercially important plant metabolites.