Engineered Microorganisms for PET Deconstruction and Upcycling
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Solution Overview
Problem
The biodegradability of poly(ethylene terephthalate) (PET) is limited due to its ester linkage, leading to environmental pollution, and chemical recycling is costly, necessitating alternative strategies for recycling and reusing PET.
Innovation Solution
Genetically modified organisms, such as Pseudomonas putida, engineered with exogenous genes encoding PETase and MHETase enzymes, capable of metabolizing PET into monomers like TPA, ethylene glycol, and other products, utilizing heterologous TPA transporters and catabolic pathways from Comamonas sp. E6 and Rhodococcus jostii RHA1, enabling bioconversion to high-value chemicals like β-ketoadipate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If chemical recycling is used to convert PET back to PET, then PET can be recycled, but the extra costs are not justified
Solution Approach 1:
The patent replaces chemical recycling methods with a biological system using genetically modified microorganisms that secrete PET-degrading enzymes. This substitution of chemical processes with biological processes aims to reduce costs while maintaining recycling capability, directly addressing the technical contradiction between recycling cost and recycling option availability
Solution Approach 2:
The genetically modified microorganisms are engineered to autonomously degrade PET and convert it into valuable products. The system uses the microorganisms' own metabolic pathways and enzyme secretion mechanisms to perform the recycling function without requiring external chemical inputs, thereby reducing operational costs while providing a viable recycling option
2Ease of operation
If PET is disposed of into the environment, then disposal is simple, but it poses a serious threat to the biosphere
Solution Approach 1:
The patent converts the harmful environmental persistence of PET into a beneficial process by engineering microorganisms to degrade PET and produce valuable chemical products. The same PET that would otherwise pollute the environment becomes a substrate for producing high-value chemicals, simultaneously eliminating pollution and creating economic value
Solution Approach 2:
The patent changes the biological parameters of the microorganisms through genetic modification to enable them to degrade PET. By altering the microorganisms' enzymatic capabilities and metabolic pathways, the system transforms PET from an environmentally persistent pollutant into a biodegradable substrate that can be converted into valuable products
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 engineered strains efficiently degrade PET into monomers, facilitating the production of high-value chemicals, overcoming the limitations of PET biodegradability and chemical recycling costs.
Implementation Method 1
the exogenous gene addition encodes functional enzymes comprising a PETase and a MHETase, and the genetically modified organism is capable of metabolizing poly (ethylene terephthalate) (PET) to produce PET deconstruction products
Data Source
AI summary
Disclosed herein are engineered P. putida KT2440 co-expressing PETase and MHETase enzymes that selectively degrades PET into monomers, ethylene glycol and terephthalate (TPA). In another embodiment, disclosed herein are methods for making and using a highly efficient EG metabolizing P. putida KT2440 strain. Given that native P. putida does not have a TPA metabolic pathway, nor the proteins to transport TPA into the cell, the next metabolic engineering challenge for developing synthetic P. putida strain to plastic upcycling was enabling TPA catabolismin P. putida KT2440. TPA transporters and catabolic pathway have been characterized in several microorganisms including Comamonas sp. strain E6 and Rhodococcus jostii RHA1.