Abstract: This work aims at exploring the possibility of preparing for esterified konjac glucomannan(KGM) derivatives via a biocatalyzed reaction and establishing a new method for the enzymatic modification of a natural polymers.In order to select appropriate biocatalysts,the catalytic ability of 8 lipases and 5 proteinases were primarily evaluated by means of the transesterification of KGM with vinyl acetate in a solvent-free system.The effect of non-aqueous reaction media on the transesterification of KGM was investigated with Novozym 435 as a biocatalyst.The results indicate that the enzymes used in the experiments possess catalytic activity for the reaction to a certain extent under the adopted conditions,and these organic solvents,dimethyl acetamide(DMAC),toluene and isooctane(IOCT),as well as the other non-aqueous organic media such as ionic liquid HMim~ ~-and a reverse micelle system AOT/IOCT,are all favorable for the Novozym 435-catalyzed transesterification of KGM with vinyl acetate.