PHA Copolymer Biosynthesis With Long-Chain 3HA for Low-Temperature Strength
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Solution Overview
Problem
Existing methods for producing PHA copolymers fail to produce a PHA copolymer containing a high proportion of 3-hydroxyalkanoate monomer units having 8 or more carbon atoms in the polyhydroxyalkanoate copolymer, resulting in the need for improved mechanical properties in low-temperature environments.
Innovation Solution
A polyhydroxyalkanoate polymer production method involving the use of a transformed microorganism having an introduced exogenous gene encoding a Class 2 PhaC derived from the genus Mycobacterium, Mycolicibacterium, or Nocardioides. The polymerization of the polyhydroxyalkanoate polymer is produced by culturing a transformed microorganism having an introduced exogenous gene encoding a Class 2 PhaC derived from the genus Mycobacterium, Mycolicibacterium, or Nocardioides. The polymerization of the polyhydroxyalkanoate polymer is produced by culturing a transformed microorganism having an introduced gene encoding a Class 2 PhaC derived from the genus Mycobacterium, Mycobacterium, or Nocardioides. The polymerization of the polyhydroxyalkanoate polymer is produced by culturing a transformed microorganism having an introduced gene encoding a Class 2 PhaC derived from the genus Mycobacterium, Mycolicibacterium, or Nocardioides.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If PHAs composed of 3-hydroxyalkanoate monomer units having 4 to 6 carbon atoms are produced, then the PHA can be manufactured using existing methods, but the glass transition temperature is around 0°C and mechanical properties decline in low-temperature environments
Solution Approach 1:
The patent changes the carbon atom parameter of the monomer units from 4-6 carbon atoms to 8 or more carbon atoms (medium-chain-length 3HAs). This parameter change directly lowers the glass transition temperature while maintaining manufacturability through the transformed microorganism system
Solution Approach 2:
The patent creates a composite PHA copolymer structure containing both 3HB units and medium-chain-length 3HA units (8 or more carbon atoms). This composite structure combines the benefits of existing PHA manufacturability with the low glass transition temperature properties of medium-chain-length monomers
2Productivity
If Class 2 PhaC from Pseudomonas genus is introduced to produce PHA copolymer containing medium-chain-length 3HA monomer units, then polymerization activity for 6 to 14 carbon atoms is achieved, but the proportion of 3HA monomer units having 8 or more carbon atoms in the copolymer is insufficient
Solution Approach 1:
The patent applies local quality by selecting specific Class 2 PhaC enzymes from particular genera (Mycobacterium, Mycolicibacterium, or Nocardioides) that have optimized catalytic properties for incorporating medium-chain-length 3HA units. This localized enzyme selection achieves both high polymerization activity and precise control over monomer unit proportion
Solution Approach 2:
The transformed microorganism system incorporates feedback mechanisms where the introduced Class 2 PhaC gene from specific genera produces enzymes that selectively polymerize medium-chain-length 3HA monomers, thereby controlling the final copolymer composition to contain a high proportion of 8 or more carbon atom units
3Productivity
If conventional methods using Pseudomonas or introduced Class 2 PhaC genes are used, then PHA copolymer production is achieved, but the proportion of 3-hydroxyalkanoate monomer units having 8 or more carbon atoms fails to be sufficiently high
Solution Approach 1:
The patent changes the genetic parameter by introducing Class 2 PhaC genes from specific genera (Mycobacterium, Mycolicibacterium, or Nocardioides) into the microorganism. This genetic parameter change results in enzymes that produce copolymers with sufficiently high proportions of medium-chain-length monomer units while maintaining high productivity
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 polymerization of the polyhydroxyalkanoate polymer is improved by using a transformed microorganism that can produce a polyhydroxyalkanoate polymer containing a high proportion of 3-hydroxyalkanoate monomer units having 8 or more carbon atoms, resulting in improved mechanical properties in low-temperature environments.
Implementation Method 1
PhaCs of Class 2 have polymerization activity for 3-hydroxyalkanoates having 6 to 14 carbon atoms
Data Source
AI summary
A transformed microorganism having an ability to produce a polyhydroxyalkanoate copolymer containing 3-hydroxyalkanoate monomer units having 8 or more carbon atoms includes: an exogenous gene encoding a polyhydroxyalkanoate synthase having an amino acid sequence of any one of SEQ ID NOS: 1 to 4; or an exogenous gene encoding a protein that has an amino acid sequence having a sequence identity of at least 90% with the amino acid sequence of any one of SEQ ID NOS: 1 to 4 and that has polyhydroxyalkanoate synthase activity.