Excretory expression of IsPETase in E. coli by an enhancer of signal peptides and enhanced PET hydrolysis

The PET hydrolase from Ideonella sakaiensis ( Is PETase) is efficient for PET degradation, which provides a promising solution for environmental contamination by plastics. This study focuses on improving the excretion of Is PETase from E. coli by signal peptide (SP) engineering. A SP enhancer B1 (MERACVAV) was fused to the N-terminal of commonly-used SP (PelB, MalE, LamB, and OmpA) to mediate excretion of Is PETase. Strikingly, the modified SP B1OmpA, B1PelB, and B1MalE significantly increased the excretion of Is PETase, while Is PETase was basically expressed in periplasmic space without enhancer B1. The excretion efficiency of Is PETase mediated by B1PelB was improved by 62 folds compared to that of PelB. The hydrolysis of PET by crude Is PETase in culture solution was also enhanced. Furthermore, the amount of released MHET/TPA from PET by Is PETase was increased by 2.7 folds with pre-incubation of hydrophobin HFBII. Taken together, this work may provide a feasible strategy for the excretion and application of the Is PETase.