Fluorescence-activated Screening of Polyester-depolymerizing Enzymes
Based on Pseudo-PET Polythioester Plastics
Abstract
Fluorescence-based high-throughput screening approaches facilitate the
discovery of enzymes and microorganisms for polyethylene terephthalate
(PET) depolymerization and recycling. However, the traditional method of
activating the fluorescence signal by cleaving the ester bond on small
molecule probes has limited ability in detecting enzymatic activity
towards polymeric substrates. This study proposes a novel
fluorescence-based screening strategy that detects the release of
sulfhydryl groups during the depolymerization of pseudo-PET
polythioesters by polyesterases. The strategy successfully identifies
the polyester-depolymerizing activity of leaf-branch compost cutinase
(LCC ICCG), while porcine liver esterase (PLE) only
hydrolyses small molecular substrates. When combined with a droplet
microfluidic system, the strategy enables high-throughput screening of
LCC ICCG. The study also demonstrates that screening
for polyester-depolymerizing bacteria can be performed via a microplate
reader platform. The new screening approach offers an efficient method
for identifying enzymes and microbial resources for depolymerizing
polyester-like plastics.