LIPASE-CATALYZED POLYESTER SYNTHESIS

The effects of residual enzyme activity, stepwise addition of lipase a t different reaction times, and enzyme quantity in direct polyesterifi cation of sebacic acid and 1,4-butanediol catalyzed by a lipase from R hizomucor miehei were investigated. Although the lipase activity dropp ed sharply in the beginning period of the reaction, the molar mass of the polyester increased rapidly, up to 39,000 g mol(-1) in 72 h. The r esidual lipase activity (hydrolytic) was only 14 %. Stepwise addition of lipase did not improve polyester synthesis. Highest mass average mo lar mass of 56,000 g mol(-1) was obtained with 0.125 g of lipase (28.5 %, w/w) in 5 days.