Benzyl butyrate esterification mediated by immobilized lipases: Evaluation of batch and fed-batch reactors to overcome lipase-acid deactivation

In this work, benzyl butyrate was synthesized for the first time via biotechnological esterification of benzyl alcohol and butyric acid in a solvent-free system (SFS). The synthesis was maximized in batch reactors, considering a low substrates molar ratio of 1:1. Novozym 435, a well-known commercial immobilized lipase (Candida antarctica fraction B - Cal B), was the best biocatalyst in the benzyl butyrate synthesis reaching 80% of conversion, followed by the NS 88011, a new lipase prepared with low-cost non-commercial material (Cal B) (46% of conversion). The butyric acid acted as an enzyme deactivator and the excess of alcohol played an important role in the performance of the immobilized enzymes. A fed-batch strategy was employed to overcome the drawbacks related to the use of alcohol in excess, and the results showed that the Novozym 435 had the activity preserved over many cycles of esterification. The scale-up of the fed-batch reactor showed that Novozym 435 had a good and viable performance in the benzyl butyrate esterification at a molar ratio of 1:1 and SFS.