Synthesis of propyl gallate by transesterification of tannic acid in aqueous media catalysed by immobilised derivatives of tannase from Lactobacillus plantarum

Immobilised derivatives of tannase from Lactobacillus plantarum were able to catalyse the transesterification of tannic acid by using moderate concentrations of 1-propanol in aqueous media. Transesterification of tannic acid was very similar to transesterification of methyl gallate. The synthetic yield depended on the pH and concentration of 1-propanol, although it did not vary much when using 30% or 50% 1-propanol. Synthetic yields of 45% were obtained with 30% of 1-propanol at pH 5.0. The product was chromatographically pure, and the reaction by-product was 55% pure gallic acid. On the other hand, immobilised tannase was fairly stable under optimal reaction conditions.This work has been supported by Grants AGL2008-01052, AGL- 2009-07625, Consolider INGENIO 2010 CSD2007-00063 FUN-CFOOD (CICYT), RM2008-00002 (INIA), and S-0505/AGR/000153 (CAM). J.A. Curiel is a recipient of pre-doctoral fellowships from the I3P-CSIC Program and FPI-MEC, and Gloria Fernández-Lorente is a recipient of Ramon y Cajal postdoctoral ContractPeer reviewe