Enzyme Complex for PET Decomposition via Dockerin-Cohesin Binding
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Solution Overview
Problem
Polyethylene terephthalate (PET) plastics are difficult to decompose naturally and existing physical treatment methods emit secondary environmental pollutants, necessitating a biological decomposition method that effectively breaks down PET into reusable monomers.
Innovation Solution
A recombinant enzyme complex is developed by fusing PETase and lipase with a dockerin module to a mini-scaffolding protein containing a cohesin and carbohydrate binding module, enhancing the decomposition efficiency of PET through dockerin-cohesin binding, forming a stable enzyme complex that synergistically decomposes PET into terephthalic acid and ethylene glycol.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If physical treatment method (high temperature and high pressure) is used to decompose PET, then decomposition effectiveness is improved, but secondary environmental pollutants are emitted
Solution Approach 1:
The patent replaces the physical treatment method (mechanical/thermal system) with a biological treatment method using enzyme complexes. Specifically, it employs a multi-enzyme complex containing PETase, lipase, and cutinase that works at ambient temperatures and pressures, substituting the high-temperature high-pressure mechanical system with a biochemical system that decomposes PET into monomers without emitting secondary pollutants
Solution Approach 2:
The patent changes the operating parameters from high temperature and high pressure to ambient temperature and pressure. The enzyme complex functions optimally at mild conditions, fundamentally altering the physical parameters of the decomposition process to eliminate harmful emissions while maintaining decomposition effectiveness
2Object-generated harmful factors
If biological treatment method using single enzyme is used to decompose PET, then environmental safety is improved, but decomposition efficiency is insufficient
Solution Approach 1:
The patent merges multiple enzymes (PETase, lipase, and cutinase) into a single enzyme complex structure. This combination allows the system to maintain environmental safety while significantly improving decomposition efficiency through synergistic effects. The complex structure enables coordinated action of different enzymatic functions on the PET substrate
Solution Approach 2:
The patent creates a composite enzyme system by combining different enzymatic components with complementary functions. The composite structure includes PETase for initial PET hydrolysis, lipase for further degradation, and cutinase for complete breakdown, forming a multi-functional composite that enhances overall decomposition efficiency while remaining environmentally safe
3Productivity
If enzyme complex with multiple enzymes is used to decompose PET, then decomposition efficiency is improved, but system complexity increases
Solution Approach 1:
The patent organizes the multiple enzymes within a nested complex structure where a scaffolding protein provides a framework that houses and positions the individual enzymatic components. This nested arrangement allows the system to achieve high decomposition efficiency through multiple enzymes while managing complexity through a structured, hierarchical organization where the scaffolding protein integrates all components into a coordinated unit
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The enzyme complex efficiently decomposes PET, offering a cost-effective and environmentally safe solution for PET recycling, producing reusable chemical precursors and improving accessibility to the substrate, thus addressing the challenges of PET decomposition and pollution from traditional methods.
Implementation Method 1
a fusion protein 1 to which PETase and a dockerin module bind; and a fusion protein 2 to which lipase and a dockerin module bind; are linked to a mini-scaffolding protein including a cohesin module and a carbohydrate binding module by dockerin-cohesin binding
Implementation Method 2
The decomposition process of polyethylene terephthalate (PET) is performed by converting the PET to bis(2-hydroxyethyl) terephthalate (BHET) and mono(2-hydroxyethyl) terephthalate (MHET) to be converted to terephthalate (TPA) and ethylene glycol (EG) as monomers
Implementation Method 3
has a carbohydrate binding module (hereinafter, simply abbreviated as 'CBM') in the scaffolding protein to improve the efficiency of enzymes forming the complex
Data Source
AI summary
Provided are an enzyme complex for decomposing polyethylene terephthalate (PET), a method for decomposing waste plastic using the enzyme complex, and a manufacturing method of the enzyme complex. According to the present disclosure, since the enzyme complex is a complex form of Ideonella sakaiensis-derived PETase and Candida Antarctica-derived lipase (CALB) by dockerin-cohesin binding and is simultaneously applicable to a substrate to be decomposed, it is possible to exhibit a synergistic effect on the decomposition of polyethylene terephthalate. In addition, it is possible to provide a stable enzyme complex of decomposing polyethylene terephthalate by providing a mini-scaffolding protein obtained by miniaturizing cellulosome as a scaffolding protein. In particular, the mini-scaffolding protein includes an A-type CBM3 module as a carbohydrate binding module to increase the accessibility to polyethylene terephthalate, a substrate to be decomposed, and to have quickly and efficiently polyethylene terephthalate decomposition activity.