Abstract: A method of obtaining glucose isomerase which comprises cultivating the enzyme-producing strain Streptomyces sp. N.765, registration No. 143 (Bulgarian State Institute for Drug Control, Sofia, Bulgaria,) for 36 to 72 hours at a temperature of 24.degree. to 36.degree. C. at an initial pH of 6.5 to 9.0 in a culture medium containing 1.0 to 2.0% xylose 1.5 to 4.0% of dry weight of maize extract and 0.23 to 1.0% weight sodium acetate.

Abstract: A method for producing glucose isomerase comprising the steps of cultivating the enzyme producing strain Streptomyces sp. 1339 registration N. 144 Bulgarian State Institute for Drug Control, for 36 to 72 hours in a culture medium with xylose as an indicator, the temperature being kept at 24.degree. to 36.degree. C., the initial pH of cultivation being from 6.5 to 9.0 and effective isomerization at a temperature of 50.degree. to 80.degree. C., and a pH of 6.0 to 9.0 in the presence of 1.times.10.sup.-4 M CoCl.sub.2.6H.sub.2 O 1.times.10.sup.-2 M MgSO.sub.4.7H.sub.2 O in 0.1 to 3 M of the substrate.