PRODUCTION OF DEXTRANSUCRASE IN FREE OR IMMOBILIZED LEUCONOSTOC CULTURES

Abstract

Dextransucrase enzyme is responsible for the synthesis of dextran from sucrose. 'Flus enzyme is an extracellular inducible enzyme. The produc­ tion of dextransucrase enzyme by free and immobilized Leuconostoc mesentero!des cells, was studied under different physiological conditions, Purification, immobilization and determination of some ) properties of the free and immobilized enzyme were also taken under ' consideration.

1. In prelinlinary experiments of the present work, the time course of dextran production by L. mesenteroides was studied. The maximum yield of dextran and the highest enzyme activity were obtained after 42 h.

2. The composition and concentration of different nutrients fonning the cultivation medium were studied and optimized as well as other conditi0ns affecting the biosynthesis of dextransucrase enzyme by L. mesenteroides. Different sucrose concentrations were tested. 100 g/1 sucrose level was the best one.

3. The h,ighest enzyme activity was attained when the culture medium was supplemented with 1 g yeast extract/!.

4. The effect of some nutrients on dextransucrase yield was studied. 0.4 g/1 MgS04 .7H20 and 2 g/1 K2HP04 were conducive to highest enzyme activity.