DESCRIPTION: (Applicant's abstract) The development of enzyme biocatalysts that are reusable and able to work in heterogeneous reaction systems is the focus of this proposal. A reversibly soluble polymer is to be attached to the enzymes. Consequently, the biocatalyst can be precipitated without enzyme denaturation after product separation. Later the biocatalyst can be dissolved again in a suspension of the starting materials at the initial conditions. Therefore, these biocatalysts acquire the advantages of free enzymes (high activity in heterogeneous systems) and of immobilized enzymes (the possibility of a reuse). Biocatalysis is underutilized in industry due to the industry requirement that the biocatalyst should be reusable and the reaction has a high throughput. Solubility of the compounds in limited and this necessitates running the reaction in heterogeneous suspension of the starting materials and the products. However, today all biocatalysts on the market either cannot be reused or do not work in heterogeneous systems. Feasibility of the idea was demonstrated on during Phase I. Phase II focuses on the optimization of the process using the enzymes of industrial interests. These biocatalysts will be marketed to pharmaceutical companies and used to manufacture chiral pharmaceuticals. In 2000, the market for such biocatalysts is about $200 million. PROPOSED COMMERCIAL APPLICATION: The enzyme biocatalysts described in proposal are unique because they combine advantages of free and immobilized enzymes. There are no biocatalysts of this kind commercially available and an enormous commercial potential exists because most drugs are developed in a single enantiomer form. Sales of the reversibly soluble biocatalyst for a production of just one drug can generate up to several million US dollars per year.