Hydrophobic cell surface display system of PETase as a sustainable biocatalyst for PET degradation

Yunpu Jia; Nadia A Samak; Xuemi Hao; Zheng Chen; Qifeng Wen; Jianmin Xing

doi:10.3389/fmicb.2022.1005480

Hydrophobic cell surface display system of PETase as a sustainable biocatalyst for PET degradation

Front Microbiol. 2022 Sep 29:13:1005480. doi: 10.3389/fmicb.2022.1005480. eCollection 2022.

Authors

Yunpu Jia^{1

2}, Nadia A Samak³, Xuemi Hao^{1

2}, Zheng Chen^{1

2}, Qifeng Wen^{1

2}, Jianmin Xing^{1

2

4}

Affiliations

¹ CAS Key Laboratory of Green Process and Engineering, State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, China.
² College of Chemical Engineering, University of Chinese Academy of Sciences, Beijing, China.
³ Environmental Microbiology and Biotechnology, Aquatic Microbiology, University of Duisburg-Essen, Essen, Germany.
⁴ Chemistry and Chemical Engineering Guangdong Laboratory, Shantou, China.

Abstract

Remarkably, a hydrolase from Ideonella sakaiensis 201-F6, termed PETase, exhibits great potential in polyethylene terephthalate (PET) waste management due to it can efficiently degrade PET under moderate conditions. However, its low yield and poor accessibility to bulky substrates hamper its further industrial application. Herein a multigene fusion strategy is introduced for constructing a hydrophobic cell surface display (HCSD) system in Escherichia coli as a robust, recyclable, and sustainable whole-cell catalyst. The truncated outer membrane hybrid protein FadL exposed the PETase and hydrophobic protein HFBII on the surface of E. coli with efficient PET accessibility and degradation performance. E. coli containing the HCSD system changed the surface tension of the bacterial solution, resulting in a smaller contact angle (83.9 ± 2° vs. 58.5 ± 1°) of the system on the PET surface, thus giving a better opportunity for PETase to interact with PET. Furthermore, pretreatment of PET with HCSD showed rougher surfaces with greater hydrophilicity (water contact angle of 68.4 ± 1° vs. 106.1 ± 2°) than the non-pretreated ones. Moreover, the HCSD system showed excellent sustainable degradation performance for PET bottles with a higher degradation rate than free PETase. The HCSD degradation system also had excellent stability, maintaining 73% of its initial activity after 7 days of incubation at 40°C and retaining 70% activity after seven cycles. This study indicates that the HCSD system could be used as a novel catalyst for efficiently accelerating PET biodegradation.

Keywords: PET biodegradation; PETase; extracellular protein production; polyethylene terephthalate; surface display; whole-cell catalysis.