Polyethylene terephthalate (PET) becomes one of the most well-known polyesters and is widely used as packaging material. Recently, polyethylene terephthalate hydrolase (PETase) has emerged as a potential biocatalyst demonstrating the ability to degrade polyethylene terephthalate (PET). We showed that the rate of PETase hydrolysis could be significantly increased in the presence of hydrophobin RolA. Hydrophobins represent a class of small fungal protein that has a high surface-active substance and can spontaneously self-assemble at hydrophilic-hydrophobic interfaces. In this work, a class I hydrophobin named RolA was extracted from the mycelium pellet collected from a fermentation culture of Aspergillus oryzae. The SDS-PAGE analysis of the isolated RolA showed the presence of 11 kDa polypeptide. Recombinant PETase from Ideonella sakaiensis was also successfully expressed in Escherichia coli as a soluble protein with molecular weight approximately 30 kDa. The hydrophobin RolA could enhance the PET hydrolysis in the presence of the recombinant PETase. The hydrolysis of PET bottle by RolA-PETase achieved the highest weight loss of 26% in 4 days. It is speculated that the wetting effect of RolA acts on PET surface converts PET to become hydrophilic that leads PETase easier to contact and attack the surface.

Graphical Abstract

聚对苯二甲酸乙二醇酯 (PET) 成为最知名的聚酯之一，被广泛用作包装材料。最近，聚对苯二甲酸乙二醇酯水解酶 (PETase) 已成为一种潜在的生物催化剂，展示了降解聚对苯二甲酸乙二醇酯 (PET) 的能力。我们表明，在疏水蛋白 RolA 的存在下，PETase 水解的速率可以显着增加。疏水蛋白是一类具有高表面活性物质的小型真菌蛋白，可以在亲水-疏水界面自发自组装。在这项工作中，从米曲霉发酵培养物中收集的菌丝体颗粒中提取了一种名为 RolA 的 I 类疏水蛋白. 分离的 RolA 的 SDS-PAGE 分析表明存在 11 kDa 多肽。来自Ideonella sakaiensis 的重组 PETase也在大肠杆菌中成功表达为分子量约为 30 kDa 的可溶性蛋白质。在重组 PETase 存在的情况下，疏水蛋白 RolA 可以增强 PET 水解。RolA-PETase 对 PET 瓶的水解达到了 26% 的最高重量损失在 4 天内。据推测，RolA 的润湿作用作用于 PET 表面，使 PET 转变为亲水性，使 PETase 更容易接触和攻击表面。

图形概要