Combination use of microwave irradiation and ionic liquid in enzymatic isomerization of xylose to xylulose

Combination use of microwave irradiation as heating mode and ionic liquid (IL) as additives was employed in isomerization of xylose to xylulose by immobilized xylose isomerase. Both microwave irradiation and IL [EMIM][Cl], which was screened as the best medium for this reaction, were found to increase the enzyme activity and xylulose yield in isomerization reaction. And a further increase of enzyme activity and xylulose yield were observed by combination use of microwave irradiation and IL. A systematic screening and optimization of the reaction parameters in ILs under microwave irradiation of the isomerization were performed. Under the optimum reaction condition, xylulose was obtained at 68% yield in 3 h. Furthermore, increased thermal stability of immobilized xylose isomerase was also observed by combination use of microwave irradiation and IL. These results indicated that the combination use of microwave irradiation and IL was a fast and efficient method for enzymatic isomerization of xylose to xylulose.