Abstract

M. G. Aziz*, Y. A. Yusof and K. D. Kulbe

This work is concerned with the production of glucose-fructose oxidoreductase (GFOR) enzyme for converting pineapple juice sugars into dietetic derivatives. GFOR was produced from Zymomonas mobilis by sub-merge fermentation of 10 L. During fermentation, the highest biomass formation was observed at 24 h and the highest enzyme activity per g biomass was observed at 27 h of fermentation. Cells were isolated by centrifugation, broken down by high pressure homogenizer, enzyme separated by centrifugation and finally the enzyme was purified on a dye substituted column. Electrophoresis of separated fractions confirmed its structure showing a band at 40 kD. Application of GFOR successfully converted pineapple juice sugars; fructose and glucose into sorbitol, a low calorie sugar alcohol, and gluconic acid, respectively. This enzyme was found highly efficient in case of converting juice sugars of fruits juices having higher natural pH.