Operational stability of subtilisin CLECs in organic solvents in repeated batch and in continuous operation

The operational stability of cross-linked crystals (CLECs) of subtilisin Carlsberg in organic media is compared between repeated batch and continuous flow operation. The study was designed to create similar conditions in the two modes, although these can never be identical in all respects. The biocatalyst inactivates rapidly during the first two batches of 2 h each, losing 50% or more of its activity. The inactivation becomes slower over the following longer batches of 24 h. This pattern of rapid and slower phases of inactivation is similar to that observed in continuous reactors. However, in both acetonitrile and tetrahydrofuran, inactivation is somewhat faster over the first 4 h of continuous operation than in the equivalent batch mode.