Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) containing 5 and 17 mol% 3-hydroxyhexanoate has been blended with atactic poly(3-hydroxybutyrate) (PHB), polycaprolactone (PCL), and polybutylene succinate (PBS) at different ratios by the solvent-casting method. PHBH-5%/atactic PHB and PHBH-17%/atactic PHB showed a single glass-transition temperature (T_g), indicating miscibility in the amorphous state. Immiscibility was observed in the PHBH-5%/PCL and PHBH-17%/PCL blends based on the non-transitioning T_g of the PHBH component, presence of two distinct T_g values for some of the blend films, and individual crystallization manner. The thermal properties and spherulitic morphologies of the PHBH-5%/PBS blend films suggested partial miscibility. The enzymatic degradability of the three types of blends by Ralstonia pickettii T1 PHB depolymerase and Burkholderia cepacia lipase was investigated. Depending on the enzyme–substrate specificity, miscibility, and phase structure of the blend, the variation of the enzymatic degradation rate with the blend ratio was different among the three types of blends. The weight loss rate of PHBH-5%/atactic PHB was higher than that of PHBH-17%/atactic PHB when degraded by PHB depolymerase. The PCL component accelerated the weight loss rate of PHBH-17%/PCL but decreased that of PHBH-5%/PCL. Lipase barely eroded PHBH-5%/PBS, but the weight loss rate increased as the PCL content increased. From quantitative analysis of the water-soluble products liberated during degradation, the degradation manners of the blends by PHB depolymerase and lipase are discussed.

含有 5 和 17 mol% 3-羟基己酸酯的聚（3-羟基丁酸酯-共-3-羟基己酸酯）（PHBH）与无规立构聚（3-羟基丁酸酯）（PHB）、聚己内酯（PCL）和聚丁二酸丁二醇酯（PBS）混合通过溶剂浇铸法以不同的比例。PHBH-5%/无规立构 PHB 和 PHBH-17%/无规立构 PHB 显示出单一的玻璃化转变温度 ( T _g )，表明在无定形状态下可混溶。混溶是在PHBH-5％观察/ PCL和PHBH-17％/基于所述非过渡PCL共混物Ť_克的PHBH组分，两个不同的存在Ť_克某些共混薄膜的值和个别结晶方式。PHBH-5%/PBS 共混薄膜的热性能和球晶形态表明部分混溶。Ralstonia pickettii T1 PHB解聚酶和洋葱伯克霍尔德菌对三种混合物的酶促降解脂肪酶进行了研究。根据共混物的酶-底物特异性、混溶性和相结构，三种共混物的酶促降解速率随共混物比例的变化不同。PHBH-5%/无规PHB在被PHB解聚酶降解后的失重率高于PHBH-17%/无规PHB。PCL组分加快了PHBH-17%/PCL的失重率，但降低了PHBH-5%/PCL的失重率。脂肪酶几乎不侵蚀PHBH-5%/PBS，但随着PCL含量的增加，失重率增加。通过对降解过程中释放的水溶性产物的定量分析，讨论了PHB解聚酶和脂肪酶对共混物的降解方式。