Advances in enzyme engineering have dramatically increased the use of novel enzyme classes and their applications to pharmaceutical synthesis. In many instances, multiple enzymes are simultaneously employed for co-factor recycling or to perform sequential synthetic steps. The high enzyme loads for these processes introduce many challenges related to protein stability and protein-product isolation, which are traditionally mitigated by process-intensive operations with significant yield loss. Novel strategies are needed to increase enzyme loading, stability, remove residual host cell proteins with off-target activity, and to facilitate product-protein separation without additional chemical isolations or purifications.
Immobilizing an enzyme to a porous resin solves many of these issues by creating a solid-supported catalyst with extremely high enzyme loads that can be prepared in advance, easily charged into a reactor, and rapidly isolated from the product by filtration. We have developed a scalable enzyme-immobilization platform technology based on IMAC to selectively co-immobilize enzyme cascades onto a single resin directly from crude cell lysate and reject host-cell proteins. In this talk, Jacob H. Forstater, Ph.D., Associate Principal Scientist, Merck Process Research & Development at Merck Research Laboratories will discuss how we utilized IMAC to enable a streamlined through-process for the biocatalytic synthesis of islatravir, a promising nucleoside analog drug for the treatment of HIV. We discuss process design principles for the development and scale-up of robust multi-enzyme biocatalytic processes and their integration into traditional small-molecule manufacturing operations.