The PET hydrolase from Ideonella sakaiensis (IsPETase) is efficient for PET degradation, which provides a promising solution for environmental contamination by plastics. This study focuses on improving the excretion of IsPETase 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 IsPETase. Strikingly, the modified SP B1OmpA, B1PelB, and B1MalE significantly increased the excretion of IsPETase, while IsPETase was basically expressed in periplasmic space without enhancer B1. The excretion efficiency of IsPETase mediated by B1PelB was improved by 62 folds compared to that of PelB. The hydrolysis of PET by crude IsPETase in culture solution was also enhanced. Furthermore, the amount of released MHET/TPA from PET by IsPETase 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 IsPETase.
Keywords: Extracellular excretion; IsPETase; Signal peptide enhancer.
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