固定化对恶臭假单胞菌腈水合酶催化特性的影响

EFFECT OF IMMOBILIZATION ON CATALYTIC PROPERTIES OF NITRILE HYDRATASE IN PSEUDOMONAS PUTIDA

酶法代替铜催化法使丙烯腈转化制内烯酰胺的研究,70年代起在国外开始进行.近年来,国内也相继开展了这方面的工作.他们筛选得到的恶臭假单胞菌JP-1具有较高腈水合酶活力,其完整细胞的腈水合酶催化特性也已进行了研究.本文研究了采用海藻酸钙包埋法制备的恶臭假单胞菌固定化细胞的酶学性质.

Immobilized Pseudomonas putida JP- 1 cells entrapped in calcium alginate was found to have high nitrile hydratase activities .The optimum temperature of acrylonitrile hydratase in immobilized cells is also 25-30 ℃, the same as that of the whole cells. But the optimum pH, pH stability, heat stability and apparent Michaelis constant(K'M) are higher than that of the whole cells under the same conditions.lt was found that EDTA and bivalent metalions such as Ca2+ , Cu2+ , Zn2+ , Mg2+, Fe2+ have no effect on nitrile hydratase of both immobilized cells and whole cells when they are added to the reaction mixture. The activity of nitrile hydratase in immobilized cells is 187 units, recovery rate of enzymic activity is 73%. When the reaction is carried out for 13 hours, 300 g/L of acrylamide is produced.