Enzymatic isomerization of glucose and xylose in ionic liquids

Abstract

Glucose isomerase has been found for the first time to catalyze the isomerization of glucose to fructose in the ionic liquid N,N-dibutylethanolammonium octanoate (DBAO). Isomerization was achieved at temperatures of 60–80 °C although a substantial amount of mannose was formed at elevated temperatures via the Lobry-de Bruyn–van Ekenstein transformation. Complete recovery of the sugars after reaction was achieved by extraction with aqueous HCl, thus making the protocol attractive for continuous operation.