Brillouet J M, Coulet P R, Gautheron D C
Biotechnol Bioeng. 1977 Jan;19(1):125-42. doi: 10.1002/bit.260190110.
Amyloglucosidase was covalently bound to collagen sheets by a previously described method. The time of acidic methylation (first step of the collagen activation process) was important to obtain a good enzymatic surfacic activity. Homogeneity of the coupling procedure on the surface of collagen films was shown. Some properties of free enzyme were not affected after grafting; optimum pH and temperature, activation energy, and Km for maltose. Heat stability of the bound enzyme was slightly better; Km for soluble starch increased fivefold. In contrast, the maximal velocity in the presence of soluble starch remained four times that of maltose hydrolysis. Amyloglucosidase collagen membranes were used in a helicoidal reactor to produce glucose from maltose or soluble starch solutions. Tracer studies have shown that the helicoidal reactor behaved as a CSTR. The influence of maltose concentration and flow rate on conversion was studied and confirmed the absence of diffusional limitations for maltose. Recycling of concentrated solutions of maltose and soluble starch indicated strong diffusional restrictions for soluble starch. The catalytic support kept all its activity for 18 days continuous operation at 40 degrees C and 80% after 17 months storage at 4 degrees C.
采用先前描述的方法将糖化酶共价结合到胶原膜上。酸性甲基化时间（胶原活化过程的第一步）对于获得良好的酶表面活性很重要。结果表明胶原膜表面偶联过程具有均匀性。接枝后游离酶的一些性质未受影响；最适pH和温度、活化能以及对麦芽糖的米氏常数。结合酶的热稳定性稍好；对可溶性淀粉的米氏常数增加了五倍。相比之下，在可溶性淀粉存在下的最大反应速度仍是麦芽糖水解反应速度的四倍。糖化酶胶原膜用于螺旋式反应器中，从麦芽糖或可溶性淀粉溶液生产葡萄糖。示踪研究表明螺旋式反应器表现为连续搅拌釜式反应器。研究了麦芽糖浓度和流速对转化率的影响，证实不存在麦芽糖的扩散限制。麦芽糖和可溶性淀粉浓缩溶液的循环利用表明存在可溶性淀粉的强扩散限制。催化载体在40℃连续运行18天仍保持全部活性，在4℃储存17个月后活性保持80%。
