用石英晶体微天平法研究聚乳酸的酶降解过程

Enzymatic Degradation of PLA by a Quartz Crystal Microbalance

利用石英晶体微天平（QCM）探讨影响聚乳酸降解速率的不同因素。聚乳酸的酶降解分两步进行：酶吸附到聚乳酸的表面和聚乳酸在酶作用下的降解。聚乳酸的降解初速率随酶加入量的增加而增大,但达到一定的加入量之后,降解初速率接近一个常数;当pH为7～9时,聚乳酸的降解初速率随pH的增大而增大;当温度为25～40℃时,降解初速率随温度的升高而增大。

The kinetics of the enzymatic degradation of PLA is investigated by quartz crystal microbalance（QCM）.There are several important factors which affect the enzymatic degradation of PLA by proteinase K.The enzymatic degradation of PLA by proteinase K is a two-step process.The first step is adsorption of the enzyme on the surface of the substrate and the second step is degradation of PLA by proteinase K.The initial degradation rate increases with the increasing enzyme concentration and attains to be constant after the enzyme concentration approaches a certain value.The initial degradation rate increases with the increasing pH in the range of pH from 7 to 9.The initial degradation rate increases with increasing temperature in the range of temperature from 25 ℃ to 40 ℃.