Subtilisin-Catalyzed Transesterifications in the Presence of Iron Oxide Nanoparticles in Organic Solvent: Dramatic Catalytic Improvement

Enzymatic transformations in organic media provide a useful methodology for the synthesis of a wide range of enantiomeric compounds.1 In spite of remarkable advances in this field, the enzymes still suffer from a limitation that they display significantly reduced activities in organic media, which are often several orders of magnitude lower than aqueous counterparts. In the past decades, intensive studies have been done to develop methods for enhancing enzymatic activity in organic media. A useful approach is the lyophilization of enzyme in the presence of excipients such as lyoprotectants, polymers, and salts.2 For example, subtilisin lyophilized in the presence of KCl salts (98%, W/ W) displayed three orders of magnitude higher activity than its salt-free counterpart in organic solvent.3 The salt– activated subtilisin as the catalyst for synthetic applications,