Screening of glucose isomerase-producing microorganisms

The ability to convert D-glucose into D-fructose was found in 14 out of 74 species of actinomycetes and bacteria tested. High intracellular glucose isomerase activity was displayed by Arthrobacter sp. and actinomycetes Streptomyces viridobrunneus, Streptomyces sp. 1 and Streptomyces sp. 32. The first showed maximal glucose-converting potential when cultured in both glucose and xylose media, while glucose isomerase activity of Streptomyces species could be found solely in medium supplemented with xylose. The ketose enzymatically formed from D-glucose was identified as D-fructose.