Abstract: Continuous enzymatic isomerization of a glucose syrup with a glucose concentration of 30-55% by weight containing less than about 10.sup.-.sup.3 M calcium, less than about 10.sup.-.sup.2 M of Mg.sup.+.sup.+, the Mg.sup.+.sup.+ being in a concentration, whereby the molar ratio of magnesium to calcium is greater than 5, the isomerization taking place at a pH 7.8-8.6 with a total contact time between enzyme and syrup less than about 3.5 hours, preferably less than 2 hours. A convenient temperature range for isomerization is 60.degree.-85.degree. C., preferably 60.degree.-70.degree. C. The syrup has no colbalt added thereto. A preferred practice involves a syrup with very little added magnesium. Post isomerization ion exchange treatment can be avoided.The enzyme is a particulate preparation derived from B. coagulans, preferably by glutaraldehyde reaction with homogenized microorganism cells.