【摘要】 在液相培养基中将米曲霉菌体培养成直径为 1～ 2mm的菌球 ,以甲醛为交联剂、明胶为活性保护剂对其进行固定化研究 .在正交实验L16(45)的基础上 ,利用人工神经网络得到了较优的固定化条件 :菌体与固定液的用量比 (固液比 ) 1∶8,固定液中含明胶 5 g·L-1、甲醛 5 g·L-1,固定化时间为 1.5h .在此条件下制备的固定化米曲霉菌体比酶活为 15 0 0U ,比酶活保留率 83% .对固定化米曲霉菌体稳定性进行深入研究表明 ,其最适反应温度和 pH值分别为 6 3℃和 8.0 ,与游离菌体相比最适反应条件范围变宽 .在固定床反应器中用其连续拆分N -乙酰 -DL -丙氨酸 ,半衰期为 77天 ,具有较高的操作稳定性更多还原

【Abstract】 Aspergillus oryzae (3042)mycelium pellets cultured in liquid were immobilized by cross-linking with gelatin and formaldehyde.Based on orthogonal design L 16 (4 5),a four-layer artificial neural network (ANN) model with back-propagation of error (BP) was used to optimize the immobilization conditions.The optimal condition was obtained.The conditions were:1?g wet pellets were added into 8?ml immobilization solution,both the concentration of gelatin and formaldehyde were 5?g·L -1 ,and the immobilization time was 1.5?h.The relative activity of immobilized preparation under the optimal condition was assayed.The relative activity was 83%,which was in good agreement with that predicted by ANN.Finally,the stabilization of immobilized preparation was studied.It illustrated that the optimum reaction condition differed from that of free pellet.Compared with free pellet,the optimum pH of reaction system changed from 7.0 to 8.0,temperature changed from 52?℃ to 63?℃,and the proper reaction condition range was increased.When the immobilized pellet preparation was used for L-alanine continuous production in a  10?mm×100?mm packed bed reactor,operational stabilization was markedly increased,and the half-life period was 77?d.The immobilized preparation had high stability,and artificial neural network can find the better conditions.更多还原