Development of a highly active engineered PETase enzyme for polyester degradation

Abstract

Polyethylene terephthalate (PET) accounts for {approx}6% of global plastic production, contributing considerably to the global solid waste stream and environmental plastic pollution. Since the discovery of PET-depolymerizing enzymes, enzymatic PET recycling has been regarded as a promising method for plastic disposal, particularly in the context of a circular economy strategy. However, as the PET degrading enzymes developed so far suffer from relatively limited thermostability, low catalytic efficiency, as well as degradation intermediate-induced inhibition, their large scale industrial applications are still largely hampered. To overcome these limitations, we used in silico protein design methods to develop an engineered Leaf-branch Compost Cutinase (LCC), named DRK3, that features enhanced thermal stability and PETase activity relative to the current gold standard LCC enzyme (LCC-ICCG). DRK3 features a 4.1{degrees}C increase in melting temperature relative to the LCC-ICCG enzyme. Under optimal reaction conditions (68{degrees}C), the DRK3 enzyme hydrolyzes amorphous PET material into TPA with a 2-fold higher efficiency compared to LCC-ICCG. Owing to its enhanced properties, DRK3 may be a promising candidate for future applications in industrial PET recycling processes. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=138 SRC="FIGDIR/small/602061v1_ufig1.gif" ALT="Figure 1"> View larger version (47K): org.highwire.dtl.DTLVardef@125688eorg.highwire.dtl.DTLVardef@f360f8org.highwire.dtl.DTLVardef@634486org.highwire.dtl.DTLVardef@127f622_HPS_FORMAT_FIGEXP M_FIG C_FIG