The effect of the alcohol moiety on the enzymatic hydrolysis of different chrysanthemic acid esters has been studied. Of all the enzymes screened, Pig liver esterase (PLE) showed the highest activity. The PLE catalysed hydrolysis was highly trans selective for the acid moiety and S-selective for the alcohol moiety. Possibly due to conformational changes, both the native and the immobilized PLE displayed very low activity for the esterification reaction in organic solvents. (c) 2005 Elsevier Inc. All rights reserved.