Integrated PET Upcycling Process Without Monomer Purification
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Solution Overview
Problem
Existing methods for recycling polyethylene terephthalate (PET) are inefficient, environmentally harmful, and require harsh conditions, with chemical recycling needing additional purification steps and biological recycling facing enzyme suppression due to pH issues.
Innovation Solution
A chemical-biological integrated process using ethylene glycol as a solvent, betaine as a catalyst, and specific enzymes to depolymerize PET into oligomers, followed by enzymatic hydrolysis to produce high-value compounds like protocatechuic acid and glycolic acid without additional purification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If chemical recycling using metal catalysts is used to decompose PET into monomers, then high-purity monomers can be obtained, but the process requires harsh conditions and additional separation and purification steps that reduce economic efficiency
Solution Approach 1:
The patent divides the recycling process into two distinct stages: (1) chemical depolymerization stage using metal catalysts to break PET into monomers, and (2) biological conversion stage using engineered microorganisms to convert monomers into high-value products. This segmentation allows each stage to be optimized independently, reducing the need for extensive purification between stages.
Solution Approach 2:
The patent introduces engineered microorganisms as an intermediary between chemical depolymerization and final product formation. These microorganisms directly consume the monomers produced by chemical catalysis and convert them into high-value compounds, eliminating the need for separate purification steps that would otherwise be required to obtain pure monomers for downstream processing.
2Object-affected harmful factors
If biological recycling using enzymes alone is used to hydrolyze PET, then the process is environmentally friendly, but enzymatic activity is suppressed due to pH changes, making practical application difficult
Solution Approach 1:
The patent merges chemical and biological recycling approaches into an integrated two-stage process. The first stage uses chemical catalysis under controlled conditions to depolymerize PET, and the second stage uses biological conversion by engineered microorganisms. This combination allows the system to overcome the limitations of each individual approach while maintaining environmental benefits.
Solution Approach 2:
The patent changes the operational parameters of the biological conversion stage by using engineered microorganisms that can tolerate and thrive in the specific pH conditions resulting from the chemical depolymerization stage. The system is designed to maintain pH within a range that preserves enzymatic activity while allowing efficient conversion of monomers to high-value products.
3Productivity
If chemical pretreatment process is introduced to create enzyme-preferred substrates, then enzymatic hydrolysis is facilitated, but the process complexity increases and requires finding suitable chemical pretreatment conditions
Solution Approach 1:
The patent applies preliminary chemical depolymerization to break down PET into monomers before the biological conversion stage. This preliminary action creates substrates that are much more accessible and reactive for the subsequent enzymatic processes, dramatically improving hydrolysis efficiency and overall product yield.
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
This process achieves high-concentration, high-yield production of valuable chemicals with reduced environmental impact and no need for additional separation or purification steps.
Implementation Method 1
glycolysis using glycol conventionally uses an ethylene glycol solvent and a metal catalyst
Implementation Method 2
glycolysis using glycol conventionally uses an ethylene glycol solvent and a metal catalyst
Implementation Method 3
PET decomposed into an oligomer by the glycolysis is decomposed into terephthalic acid and ethylene glycol using a hydrolase
Implementation Method 4
recombinant E. coli into which a recombinant plasmid having a conversion-related gene for converting TPA into PCA is inserted
Implementation Method 5
Gluconobacter oxydans (G. oxydans) KCCM 40109 with a conversion pathway to convert EG into GLA
Data Source
AI summary
The present invention relates to a chemical and biological integrated degradation process for PET, for recycling PET, and, more specifically, the present invention provides a PET upcycling technique for producing a high-value product via a chemical pretreatment process of PET, a TPA and EG production process using an enzyme, and a process for converting TPA and EG to PCA and GLA, respectively.