Abstract
A glutamine production process was established by combining alcoholic fermentation of baker's yeast cells with glutamine synthetase from the bacterium Gluconobacter suboxydans. The maximumamount of glutamine formed under optimum conditions was about 20mMin 3 hr with 80% yield based on glutamate, substrate. The fermentation proceeded in two steps: the accumulation of energy in a form of fructose 1, 6-diphosphate (FDP) by yeast fermentation of sugar based on the Harden-Young effect and the fermentation of FDPcoupled with glutamine synthetase reaction (an endergonic reaction) through an ATP-ADPsystem. The following factors were found to be important: (a) the ratio of the activities of yeast fermentation of sugar and glutamine synthetase, (b) effect of contaminating enzyme(s) in glutamine synthetase preparation, and (c) enzymatic properties of glutamine synthetase.
