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Salt leverages polyethylene terephthalate hydrolase (PETase) enzymatic activity via the predicted conformational switch
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Researchers found that salt enhances the enzymatic activity of PETase, an enzyme that breaks down PET plastic, by inducing a predicted conformational change. This discovery could help improve enzymatic plastic recycling by optimizing salt conditions to boost degradation rates.
Abstract Plastic pollution spawned a global challenge caused by the environmental accumulation of polyethylene terephthalate (PET) plastics. Ongoing remediation efforts using microbial and engineered PET hydrolyzing enzymes (PETases) are hindered by slow depolymerization activities. Here, we report the optimized reaction conditions that leveraged the PETase hydrolase activity 2 to 3.8-fold in the presence of high NaCl concentrations. Molecular dynamics simulations (MDS) were applied to model salt-dependent conformational changes of the PETase enzyme bound to a 3-unit PET polymer. MDS demonstrated that PETase interaction with flanking polymer units exhibited a striking structural disparity at low and high salt concentrations. At low salt concentrations, flanking polymer units displayed significant bending. In contrast, flanking units extended at high salt concentrations, thus residues D206, H237, and S160 of the catalytic triad positioned in close vicinity of the scissile ester bond of the polymer substrate. The resulting high salt-specific enzyme/substrate geometry can potentially facilitate hydrolysis. We theorized that a salt-dependent conformational switch could attenuate the enzyme to a broad range of natural and artificial polymers consumed as carbon sources. Altogether, new knowledge may advance the engineering of PET hydrolase enzymes and benefit bioconversion programs.
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Researchers studied how pH dramatically affects the selectivity and efficiency of a lipase enzyme when breaking down PET plastic oligomers, revealing mechanistic insights relevant to improving enzymatic plastic recycling processes. The findings highlight pH as a key variable in engineering more effective biocatalysts for plastic degradation.
The effect of ionic strength on PETase enzymes: an experimental and computational study
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Plastic degradation by enzymatic methods
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Scientists found a way to help special enzymes break down PET plastic (the material in water bottles and polyester clothing) much more efficiently by giving it a gentle pre-treatment first—like softening it up before the enzymes get to work. This matters because it could lead to better recycling methods that actually break plastic down into reusable building blocks instead of letting it pile up in landfills or break into the microplastics that end up in our water, food, and bodies.
Marine PET Hydrolase (PET2): Assessment of Terephthalate- and Indole-Based Polyesters Depolymerization
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Researchers characterized a marine enzyme (PET2) capable of breaking down PET plastic and related polyester materials under relatively mild conditions. Discovering and engineering enzymes that can degrade PET could help address the massive accumulation of PET microplastics in ocean environments.
Investigation of the halophilic PET hydrolase PET6 from Vibrio gazogenes
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When a large batch of papers lands in the Atlas, we read through it and send a short write-up of what stood out.