The feruloyl esterases FaeA1, FaeA2, FaeB1, FaeB2 from Myceliophthora thermophila Cl and MtFae1a from M. thermophila ATCC 42464 were used as biocatalysts for the transesterification of vinyl ferulate (VFA) with L-arabinose in detergentless microemulsions. The effect of parameters such as the microemulsion composition, the substrate concentration, the enzyme load, the pH, the temperature and the agitation was investigated. FaeA1 offered the highest transesterification yield (52.2 +/- 4.3%) after 8 h of incubation at 50 degrees C using 80 mM VFA, 55 mM L-arabinose and 0.02 mg FAE mL(-1) in a mixture comprising of 19.8: 74.7: 5.5 v/v/v n-hexane: t-butanol: 100 mM MOPS-NaOH pH 8.0. The ability of L-arabinose ferulate (AFA) to scavenge 2,2-diphenyl-1-picrylhy-drazyl (DPPH) radicals was significant (IC50 386.5 mu M). AFA was not cytotoxic even at high concentrations (1 mM) however was found to be pro-oxidant at concentrations higher than 20 mu M when the antioxidant activity was determined with the dichloro-dihydro-fluorescein diacetate (DCFH-DA) assay in human skin fibroblasts.