The sale price of drugs is strongly affected by the cost of purifying the product - i.e. separating the desired chemical from the reaction medium in which it is produced. This project is a study of a bioreactor that combines the production and separation stages in one unit and thus could greatly decrease final costs to consumers. Some of this high cost is due to the increased complexity of new drugs, often very complicated molecules which may exist in more than one configuration (isomer). Of these, often only one configuration has the desired properties and separating them from each other results in additional difficulties over and above those encountered when separating different compounds from each other. The configurations to be looked at are hollow-fiber modules where the enzymes (the biocatalysts) are immobilized and product is continuously removed. This has the advantage also that product concentration does not build up which normally inhibits enzyme activity. The PIs plan to measure enzyme activity and stereoselectivity and to operate a prototype reactor in this Phase I work. They are well qualified to do the research and the facilities are adequate. Funding is recommended.