固定化谷氨酸棒杆菌T6—13细胞的酶学性质研究

STUDIES ON SOME ENZYME PROPERTIES OF IMMOBILIZED CORYNEBACTERIUM GLUTAMICUM T_6-13 WHOLE-CELL

比较研究了固定化谷氨酸棒杆菌细胞和自然细胞的谷氨酸脱氢酶、异拧檬酸脱氢酶,葡萄糖-6-磷酸脱氢酶的一些性质。最适pH、温度对二者酶促反应速度的影响基本相似;pH、热稳定性固定化细胞高于自然细胞;底物表观米氏常数谷氨酸脱氢酶,异柠檬酸脱氢酶有所增大,而葡萄糖-6-磷酸脱氢酶则有所下降;辅酶表观米氏常数均有所增大。这些是影响固定化细胞应用的主要因素。

Some enzymatic properties of immobilized cells were emphatically studied and compared with those of native cells.The glutamate dehydrogenase, iso-citrate dehydrogenase and glucose-6-pbosphate dehydrogenase of immobilized cells and native cells exhibit little change at, pH and optimum temperature, but three enzyme activity of immobilized increase in pH and heat stability,The glutamate dehydrogenase, iso-citrate dehydrogenase of immobilized cells exhibited an increase in the apparent Michaelies constant (k'm), whereas gIucose-6-phosphate dehydrogenase exhibited deerease in k'm.Three of them exhibited an increase in coenzyme apparent Michaelies constant(k'm).These are main factors that affected the application of immobilized cells. Immobilized cell beads were aerobic cultured in seed culture medium, the changes of enzyme activity in beads was investigated.lt was found that enzyme activity in beads is in relation to the culture time before 100 h, them are constant after 100 h.This is very useful for fermentation of glutamate.