Enzyme-catalyzed production of sugar-based linear polyesters

We have developed an enzymatic approach to synthesize a sucrose polyester in which the sugar is an integral part of the polymer backbone. Potential uses include biodegradable plastics for diapers and hygienic products, water-treatment chemicals, and components of drug delivery systems. The bacterial alkaline protease, Proleather, has been used as an effective catalyst for sucrose polyester synthesis. The product contains sucrose as an integral part of the polyester backbone. The sucrose polyester is highly water soluble suggesting that upon light cross-linking by conventional chemical reagents a water-insoluble, yet highly water-absorbent polymer would result. The polyester is degraded by Proleather in an aqueous solution, suggesting that biodegradation can be obtained. From a practical standpoint, this work leads to a straightforward methodology for the synthesis of sugar-containing polyesters. It may be expected that other diacid moieties can be employed to alter the properties of the sucrose polymer. For example, acylation with a triacid, such as a citric acid derivative would promote crosslinking of the polymer chain. This in turn would be expected to reduce aqueous solubility without significantly altering water absorbency. Finally, other saccharides such as fructose, glucose, maltose, and lactose and oligosaccharides such as raffinose would be expected to undergo polyester synthesis in a manner similar to sucrose, thereby providing a use of byproducts of the starch, whey, and beet sugar industries.