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Publication Abstract from PubMed

As the epidemic of single-use plastic worsens, it has become critical to identify fully renewable plastics such as those that can be degraded using enzymes. Here we describe the structure and biochemistry of an alkaline poly[(R)-3-hydroxybutyric acid] (PHB) depolymerase from the soil thermophile Lihuaxuella thermophila. Like other PHB depolymerases or PHBases, the Lihuaxuella enzyme is active against several different polyhydroxyalkanoates, including homo- and heteropolymers, but L. thermophila PHB depolymerase (LtPHBase) is unique in that it also hydrolyzes polylactic acid and polycaprolactone. LtPHBase exhibits optimal activity at 70 degrees C, and retains 88% of activity upon incubation at 65 degrees C for 3 days. The 1.2 A resolution crystal structure reveals an alpha/beta-hydrolase fold typical of PHBases, but with a shallow active site containing the catalytic Ser-His-Asp-triad that appears poised for broad substrate specificity. LtPHBase holds promise for the depolymerization of PHB and related bioplastics at high temperature, as would be required in bioindustrial operations like recycling or landfill management.

Bioplastic degradation by a polyhydroxybutyrate depolymerase from a thermophilic soil bacterium.,Thomas GM, Quirk S, Huard DJE, Lieberman RL Protein Sci. 2022 Nov;31(11):e4470. doi: 10.1002/pro.4470. PMID:36222314^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.