Regulated Enoyl-CoA Hydratase Gene Expression for PHA Copolymer Control
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Solution Overview
Problem
Current methods for producing polyhydroxyalkanoate (PHA) copolymers with regulated monomer composition ratios are inefficient, leading to limited industrial applications due to instability in gene expression and lack of precise control over 3-hydroxyhexanoic acid (3HH) composition ratios, which affects the polymer's physical properties.
Innovation Solution
A microorganism with a (R)-specific enoyl-CoA hydratase gene expression regulated by modifying the nucleotide sequence upstream of the gene, allowing for controlled synthesis of PHA copolymers by adjusting the 3HH monomer pathway, enabling precise regulation of the 3HH composition ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the 3HV molar fraction in P(3HB-co-3HV) is increased to improve flexibility, then the polymer becomes more flexible, but the physical properties do not change as desirable and the polymer cannot be processed into soft-type products
Solution Approach 1:
The patent changes the chemical composition parameters by introducing 3-hydroxyhexanoic acid (3HH) monomers into the PHA copolymer structure. By controlling the 3HH composition ratio through regulated enoyl-CoA hydratase gene expression, the patent achieves a different chemical parameter combination (3HB-co-3HH copolymer) that provides superior flexibility and processability compared to simply increasing 3HV content, thus resolving the contradiction between flexibility improvement and physical property control.
2Ease of operation
If the (R)-specific enoyl-CoA hydratase gene is introduced to produce P(3HB-co-3HH) with improved flexibility, then the 3HH composition ratio can be increased, but gene expression is unstable and precise control over monomer composition ratio is difficult to achieve
Solution Approach 1:
The patent implements feedback control by modifying the nucleotide sequence upstream of the enoyl-CoA hydratase gene to create regulated expression. This allows the gene expression level to be controlled and stabilized, providing precise and reliable control over the 3HH composition ratio in the PHA copolymer, thus resolving the contradiction between achieving desired composition ratios and maintaining stable gene expression.
Solution Approach 2:
The patent changes the genetic parameter by modifying the nucleotide sequence upstream of the enoyl-CoA hydratase gene. This sequence modification regulates gene expression levels and stabilizes the expression pattern, enabling precise control over the 3HH composition ratio while maintaining reliable and stable gene expression throughout the fermentation process.
3Manufacturing precision
If wild-type Aeromonas caviae is used to produce P(3HB-co-3HH) by fermentation, then the 3HH composition ratio can reach 15-19 mol%, but the productivity is low and cell amount is insufficient for industrial application
Solution Approach 1:
The patent segments the fermentation process into two distinct phases: a growth phase where cells are cultivated to high density, and a polymer accumulation phase where PHA copolymer is produced. This segmentation allows optimization of each phase independently - achieving high cell density first, then maximizing polymer productivity, thus resolving the contradiction between achieving precise 3HH composition ratios and improving overall polymer productivity for industrial application.
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 approach allows for the production of PHA copolymers with desirable monomer composition ratios, enhancing their industrial applicability by providing a range of physical properties from hard to soft, suitable for various applications.
Implementation Method 1
a microorganism in which (R)-specific enoyl-CoA hydratase gene expression is regulated... allowing for controlled synthesis of PHA copolymers by adjusting the 3HH monomer pathway
Data Source
AI summary
This invention relates to a microorganism that produces a polyhydroxyalkanoate (PHA) copolymer with a regulated monomer composition ratio and comprises a (R)-specific enoyl-CoA hydratase gene in the genome DNA, wherein a nucleotide sequence upstream of the (R)-specific enoyl-CoA hydratase gene comprises a modification consisting of a substitution(s), a deletion(s), an insertion(s), and/or an addition(s) of one or a plurality of nucleotides so that the expression of the (R)-specific enoyl-CoA hydratase gene is regulated, and to a method for producing a PHA copolymer using the microorganism.