Studies on Glucose Isomerase of Bacteria

A bacterial strain, HN-500, having an activity of D-glucose isomerization was newly isolated from soil, and was identified to be similar to Escherichia intermedia (Werkman and Gillen) Vaughn and Levine. The strain, grown on wide varieties of carbon sources, shows definitely D-glucose isomerizing activity in the presence of arsenate. D-Fructose formed in reaction mixture was identified by paper chromatography and was isolated in crystalline form from calcium-fructose complex. In order to increase the production of D-glucose isomerase, D-glucose and ammonium nitrogen were effective carbon and nitrogen sources, respectively, but none of the metallic ions tested were effective, furthermore manganese, ferrous and ferric ions present more than 10-5M in growth medium fully repressed the enzyme formation. The cells grown on carbon sources other than D-xylose showed no activity of D-xylose isomerase.