Enzyme-catalyzed synthesis of sugar-containing monomers and linear polymers

Commercially available proteases and lipases were screened for their ability to acylate regioselectively sucrose and trehalose with divinyladipic acid ester. Opticlean M375 (subtilisin from Bacillus licheniformis) was observed to form sucrose 1′-O-adipate and trehalose 6-O-adipate in anhydrous pyridine. Novozym-435 (lipase B from Candida antarctica) catalyzed the synthesis of sucrose 6, 6′-O-divinyladipate and trehalose 6, 6′-divinyladipate in acetone. These diesters were then employed as monomers in polycondenzation reactions with various diols (aliphatic and aromatic) catalyzed by Novozym-435 in organic solvents to yield linear polyesters with M_w's up to 22,000 Da. Spectroscopic analysis confirmed that only the vinyl end groups of sugar esters reacted in the enzymatic polymerization with the diol, and not the internal sugar-adipate linkages. The two-step enzymatic strategy to yield sugar-based polyesters, which is the first report of its kind, results in higher molecular weights and faster reaction times than one-step enzymatic polyester synthesis.