Mechanistic studies on the enzymatic transesterification of polyesters

The effect of solvents on the enzymatic transesterification of aliphatic polyesters has been investigated. It has been shown that the hydrophobicity and the polarity of the solvent have little effect on the reaction, however, the molecular weight of the product depends on the solubility of the product in the medium. Above a certain molecular weight, when the product is no longer soluble in the medium, transesterification does not occur. Deuterium NMR studies have shown that transesterification tends to take place at the ends of the polymer chain rather than at random along the polymer chain.