Glucose Isomerase catalyzes the reversible isomerization of glucose to fructose and that of xylose to xylulose. The enzyme is widely used in the industrial production of high-fructose corn syrup (HFCS) as well as in bioethanol fermentation from hemicellulosic hydrolysates.Recombinant Glucose Isomerase protein (S. rubiginosus), fused to His-tag at N-terminus, was expressed in E.coli and purified using propriety chromatography techniques.