Hydrolytic degradation of poly(4-hydroxybutyrate) (P4HB) films has been studied considering media of different pH values (i.e., 3, 7 and 10) and temperatures (i.e., 37 and 55 °C). Enzymatic degradation has also been evaluated at physiological conditions using two different lipases: Pseudomonas cepacia and Rhizopus oryzae.

Different bulk and surface erosion mechanisms with random chain scissions and successive removal of monomer units have been supported through weight loss measurements, molecular weight determinations by GPC and NMR spectroscopy and changes on thermal properties by DSC. Thermal annealing during exposure to different media and even degradation influenced on the melting temperature and crystallinity of samples, as well as on the lamellar geometrical parameters as evaluated by SAXS. Enzymatic degradation was ideal to selectively eliminate the amorphous regions and highlight the spherulitic morphology. Presence of ringed textures were therefore evident in bright field optical micrographs in addition to SEM images, namely observations under polarized light was not necessary to distinguish the presence of banded spherulites. Rhizopus oryzae was revealed to be the most suitable enzyme to crop out the P4HB spherulites that form part of the initial smooth surfaces of solvent casting films. After determining the appropriate activity and exposure time, the presence of rings constituted by cooperative C-shaped edge-on lamellae and flat-on lamellae was highlighted.

考虑到不同pH值（即3、7和10）和温度（即37和55°C）的介质，已经研究了聚（4-羟基丁酸酯）（P4HB）膜的水解降解。还已经在生理条件下使用两种不同的脂肪酶：洋葱假单胞菌和米根霉进行了酶促降解评估。

通过失重测量，通过GPC和NMR光谱测定分子量以及通过DSC改变热性能，已经支持了具有随机链断裂和依次除去单体单元的不同本体和表面腐蚀机理。暴露在不同介质中甚至降解过程中的热退火会影响样品的熔融温度和结晶度，以及如SAXS评估的层状几何参数。酶促降解是选择性去除无定形区域并突出球状形态的理想选择。因此，除了SEM图像外，在明场光学显微照片中还可以看到环状纹理的存在，即，不需要在偏振光下观察即可辨别带状球晶的存在。据了解，米根霉是最适合切出P4HB球晶的酶，P4HB球晶是溶剂型流延膜初始光滑表面的一部分。在确定适当的活性和暴露时间后，强调了由协作的C形边缘在片上和扁平在片上构成的环的存在。