We report a bioinformatic workflow and subsequent discovery of a new polyethylene terephthalate (PET) hydrolase, which we named MG8, from the human saliva metagenome. MG8 has robust PET plastic degradation activities under different temperature and salinity conditions, outperforming several naturally occurring and engineered hydrolases in degrading PET. Moreover, we genetically encoded 2,3‐diaminopropionic acid (DAP) in place of the catalytic serine residue of MG8, thereby converting a PET hydrolase into a covalent binder for bio‐functionalization of PET. We show that MG8(DAP), in conjunction with a split green fluorescent protein system, can be used to attach protein cargos to PET as well as other polyester plastics. The discovery of a highly active PET hydrolase from the human metagenome—currently an underexplored resource for industrial enzyme discovery—as well as the repurposing of such an enzyme into a plastic functionalization tool, should facilitate ongoing efforts to degrade and maximize reusability of PET.
We report a bioinformatic workflow and subsequent discovery of a new polyethylene terephthalate (PET) hydrolase, which we named MG8, from the human saliva metagenome. MG8 has robust PET plastic degradation activities under different temperature and salinity conditions, outperforming several naturally occurring and engineered hydrolases in degrading PET. Moreover, we genetically encoded 2,3-diaminopropionic acid (DAP) in place of the catalytic serine residue of MG8, thereby converting a PET hydrolase into a covalent binder for bio-functionalization of PET. We show that MG8(DAP), in conjunction with a split green fluorescent protein system, can be used to attach protein cargos to PET as well as other polyester plastics. The discovery of a highly active PET hydrolase from the human metagenome-currently an underexplored resource for industrial enzyme discovery-as well as the repurposing of such an enzyme into a plastic functionalization tool, should facilitate ongoing efforts to degrade and maximize reusability of PET.
This work aims to
utilize diamond-like carbon (DLC) thin films
for bioreceptor immobilization and amperometric biosensing in a microfluidic
platform. A specific RF-PECVD method was employed to prepare DLC thin
film electrodes with desirable surface and bulk properties. The films
possessed a relatively high sp2 fraction, a moderate electrical
conductivity (7.75 × 10–3 S cm–1), and an optical band gap of 1.67 eV. X-ray photoelectron spectroscopy
(XPS) and attenuated total reflectance Fourier transform infrared
(ATR-FTIR) spectroscopy revealed a presence of oxygen-containing functional
groups on the DLC surface. The DLC electrodes were integrated into
polydimethylsiloxane (PDMS) microfluidic electrochemical cells with
the channel volume of 2.24 μL. Glucose oxidase (GOx) was chosen
as a model bioreceptor to validate the employment of DLC electrodes
for bioelectrochemical sensing. In-channel immobilization of glucose
oxidase (GOx) at the DLC surface was realized through carbodiimide
covalent linkages. Enzyme bound DLC electrode was confirmed with the
redox potential at around −79 mV vs NHE in 0.1 M phosphate
buffer pH 7.4. Amperometric flow-injection glucose sensing at a potential
of −0.45 V vs Ag in the absence of standard redox mediators
showed the increase of current response upon increasing the glucose
concentration. The sensing mechanism is based on the reduction process
of H2O2 liberated from the enzymatic activity.
The proposed model for the catalytic H2O2 reduction
to H2O on DLC electrodes was attributed to the dissociation
of C–O bonds at the DLC surface.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.