Immobilized enzymes in organic media: Determinants of water dependence. Progress statement

The overall goals of this project are to investigate the critical factors that limit commercial scale applications of enzymes in organic solvents, and to scale-up a process for the production of a precursor to a specialty polymer. The overall performance of an immobilized enzyme can be influenced by its intrinsic structure and by external factors such as water content, support, pH, etc.. We have investigated the interrelation between support morphology and water content, and its effect on overall enzyme performance. Using a lipase catalyzed inter-esterification reaction as a model, we studied the controlling factors when water content in the organic solvent is such that a micro-aqueous phase is formed. In such an environment it was found that support particle aggregation is the major cause for decline in enzyme activity. We have shown that particle porosity, as well as the use of a particular non-woven fabric as an enzyme support, could alleviate this problem. These findings are being translated into a bioreactor design. We have also studied two {open_quotes}dry{close_quotes} non-aqueous systems, where a water phase is not formed since the water content is below its solubility in the organic solvent. In one of the systems, Subtilisin catalyzed trans-esterification of vinyl acrylate with a chiral alcohol, we have demonstrated that the use of a proprietary fabric support provides a significant boost in enzyme activity. We suggest that this particular fabric with its hydrophilic fibers acts as a lyoprotectant in the process of drying the enzyme. The benefits of this material as an enzyme support and its use in a lab scale bioreactor are being studied. Preliminary experiments have also been performed with a second {open_quotes}dry{close_quotes} reaction. This is the lipase catalyzed synthesis of AlliedSignal`s new product, VEctomer 4010