Lipases and cutinases belong to esterase family and can be used as biocatalysts for poly (ɛ-caprolactone) (PCL) degradation and recycling. A number of synthetic fusion enzymes with two or more catalytic domains were reported to be superior to the parental enzymes or their mixture for many biotechnological applications but rarely for the polyester biodegradation. To develop a more efficient biocatalyst for poly (ɛ-caprolactone) (PCL) degradation and recycling, a bifunctional lipase-cutinase (Lip-Cut) constructed by end-to-end fusion was successfully overexpressed in Pichia pastoris with 0.9% of methanol induction at pH 6.0 and temperature 27 °C. Lip-Cut displayed more efficient poly (ɛ-caprolactone) degradation capability, and the weight loss of PCL film by Lip-Cut at 6 h was 13.3, 11.8 and 5.7 times higher than that by Lip, Cut and Lip/Cut mixture, respectively. GC-MS analysis of the degraded products of PCL revealed that the mainly degraded product was 6-hydroxyhexanoic acid and small ratio of ɛ-caprolactone. Our results demonstrated that the proper construction of bifunctional lipase-cutinase could enhance the synergistic action of two moieties due to the complementary properties of both enzymes in substrate specificity and hydrolysis pattern. The method provided an effective approach to engineer more efficient biocatalyst for bio-application in degradation and recycling of PCL.

脂肪酶和角质酶属于酯酶家族，可以用作聚（ε-己内酯）（PCL）降解和再循环的生物催化剂。据报道，在许多生物技术应用中，许多具有两个或多个催化结构域的合成融合酶要优于亲本酶或其混合物，但对于聚酯的生物降解却很少。为了开发一种更有效的聚（ε-己内酯）（PCL）降解和循环利用的生物催化剂，通过端到端融合构建的双功能脂肪酶-角质酶（Lip-Cut）成功在巴斯德毕赤酵母中过表达。在pH 6.0和温度27°C的条件下用0.9％的甲醇诱导。Lip-Cut显示出更有效的聚（ε-己内酯）降解能力，Lip-Cut在6 h时的PCL膜重量分别比Lip，Cut和Lip / Cut混合物高13.3、11.8和5.7倍。对PCL的降解产物的GC-MS分析表明，主要降解产物为6-羟基己酸和少量的ε-己内酯。我们的结果表明，由于两种酶在底物特异性和水解模式上的互补特性，双功能脂肪酶-角质酶的正确构建可以增强两个部分的协同作用。该方法提供了一种有效的方法来设计更有效的生物催化剂，用于生物降解PCL和回收PCL。