Immobilization of Pseudomonas fluorescens lipase on chitosan crosslinked with polyaldehyde starch for kinetic resolution of sec-alcohols

The lipase from Pseudomonas fluorescens was immobilized on chitosan beads, with polyaldehyde starch (PAS) and glutaraldehyde (GA) being compared as crosslinking agents. With PAS, the best values for activity retention (53%), immobilization efficiency (94%), and hydrolytic activity in organic medium (156 U g−1) were obtained with an aldehyde content on chitosan of 3.5 mmol mg−1. With GA, the best results were an activity retention of 33%, an immobilization efficiency of 100%, and a hydrolytic activity in organic medium of 100 U g−1. When used in the kinetic resolution of secondary alcohols, the lipase immobilized on chitosan crosslinked with PAS gave a conversion of 43% in 24 h for (RS)-1-phenylethanol, and 36% in 36 h for (RS)-1-phenylpropanol. In both cases, the enantiomeric excess of the product (eep) was higher than 99%. These are promising results that support further studies into the immobilization of lipases on modified carbohydrates for use in organic media.