ClpB Chaperone Engineering for Higher PHA Productivity
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Solution Overview
Problem
The production cost of biodegradable polyhydroxyalkanoates (PHAs) is high due to low productivity, and there is a need to enhance their production efficiency.
Innovation Solution
Introduce a gene encoding a chaperone belonging to the ClpB family or enhance its expression in a microorganism with polyhydroxyalkanoate-producing ability, specifically in bacteria like Cupriavidus necator, to increase PHA productivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional PHA production methods are used, then PHA can be produced as a biodegradable plastic, but the production cost is high due to low productivity
Solution Approach 1:
The patent changes the biological parameter of the microorganism by introducing foreign genes (polyhydroxyalkanoate synthase gene from Aeromonas caviae and chaperone gene from Escherichia coli) to alter the PHA production pathway and protein folding efficiency, thereby increasing productivity without proportionally increasing production cost
Solution Approach 2:
The patent introduces a chaperone protein as an intermediary substance that mediates between the synthesized PHA and the cellular environment, facilitating proper protein folding and preventing aggregation, which indirectly enhances PHA production efficiency and reduces overall production costs
2Productivity
If chaperone GroESL is overexpressed to increase isopropanol productivity, then isopropanol productivity increases by 9 to 18%, but there is no reported impact on polyhydroxyalkanoate productivity
Solution Approach 1:
Instead of using the previously tested chaperone GroESL for PHA production, the patent inverts the approach by selecting a different chaperone system (ClpB family from E. coli) that has not been previously evaluated for PHA production, thereby discovering a new effective combination for enhancing PHA productivity
3Productivity
If a gene encoding a chaperone belonging to the ClpB family is introduced or its expression is enhanced, then polyhydroxyalkanoate productivity increases, but the device complexity increases
Solution Approach 1:
The patent segments the genetic engineering process into distinct functional modules: a polyhydroxyalkanoate synthase gene for PHA synthesis and a chaperone gene for protein folding assistance. This modular approach allows independent optimization of each function while managing the overall genetic complexity
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 transformed microorganism achieves high polyhydroxyalkanoate productivity even under stress conditions, reducing production costs and enhancing PHA accumulation.
Implementation Method 1
Chaperone ClpB functions to unfold and disaggregate aggregated proteins
Implementation Method 2
polyhydroxyalkanoate synthase gene; a gene encoding a chaperone belonging to the ClpB family
Data Source
AI summary
A transformed microorganism having an ability to produce a polyhydroxyalkanoate includes a polyhydroxyalkanoate synthase gene and a gene encoding a chaperone belonging to the ClpB family. The gene encoding the chaperone belonging to the ClpB family is a gene which has been introduced into the transformed microorganism or whose expression has been enhanced in the transformed microorganism. The chaperone belonging to the ClpB family may be derived from the genus Cupriavidus, Escherichia, or Saccharomyces. A polyhydroxyalkanoate can be produced by culturing the transformed microorganism.