Recombinant Yeast GAPN Pathway for ATP-Sparing 3-HP Production
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Solution Overview
Problem
Current methods for producing 3-hydroxypropionic acid (3-HP) using yeast are inefficient due to challenges such as enzyme compartmentalization, difficulty in pathway engineering, and low tolerance of yeast strains to acidic conditions, leading to suboptimal production rates and economic viability issues in large-scale fermentation.
Innovation Solution
Development of recombinant yeast cells with an active 3-HP pathway comprising a non-phosphorylating NADP-dependent glyceraldehyde-3-phosphate dehydrogenase (GAPN) and other heterologous polynucleotides, which enhance 3-HP production by bypassing ATP generation and optimizing NADPH production, thereby increasing extracellular 3-HP levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If yeast is used for 3-HP production, then advantages over bacteria (amino acid synthesis, no phage infection) are achieved, but enzyme compartmentalization and pathway engineering difficulty occur
Solution Approach 1:
The patent divides the 3-HP biosynthetic pathway into distinct enzymatic steps and introduces them as separate heterologous genes (GAPN, ADC, BAAT) into the yeast genome. This segmentation allows independent optimization and control of each pathway step, addressing the compartmentalization issue by systematically placing enzymes in appropriate cellular locations while maintaining pathway functionality.
Solution Approach 2:
The patent uses heterologous genes from bacteria (E. coli) as intermediaries to transfer the 3-HP pathway capabilities into yeast. These bacterial pathway enzymes serve as mediators that bridge the metabolic capabilities between bacterial and yeast systems, enabling 3-HP production in yeast while leveraging yeast's advantageous fermentation properties.
2Productivity
If traditional yeast pathways are used, then natural fermentation capability is maintained, but 3-HP production yield is insufficient
Solution Approach 1:
The patent performs preliminary genetic engineering by introducing and optimizing the complete heterologous 3-HP pathway (GAPN-ADC-BAAT) into the yeast genome before large-scale fermentation. This preliminary pathway construction and optimization ensures that the yeast cells are pre-equipped with high 3-HP production capability, eliminating the need for complex modifications during the fermentation process itself.
Solution Approach 2:
The patent optimizes various parameters including gene expression levels, enzyme activity ratios, and pathway flux distribution to maximize 3-HP production. By changing these biochemical parameters and tuning the heterologous pathway expression, the yeast achieves high productivity while maintaining ease of manufacture through systematic parameter optimization rather than complex structural modifications.
3Productivity
If bacteria are used for organic acid production, then high production rates are achieved, but medium buffering is required which complicates recovery
Solution Approach 1:
The patent copies the high-productivity organic acid pathway from bacteria into yeast, creating a yeast-based system that replicates bacterial 3-HP production capabilities. This copying approach allows achieving high production rates similar to bacteria while utilizing yeast's natural ability to thrive in acidic conditions, thereby eliminating the need for medium buffering and simplifying the recovery process.
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 recombinant yeast cells significantly increase 3-HP production, achieving higher yields compared to cells without the GAPN expression, making the process more economically viable for industrial-scale production.
Implementation Method 1
The recombinant yeast cells comprise a non-phosphorylating NADP-dependent glyceraldehyde-3-phosphate dehydrogenase (GAPN)
Implementation Method 2
yeast to ferment sugars to organic acids
Data Source
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AI summary
Provided herein are recombinant yeast cells having an active 3-Hydroxypropionic Acid (3-HP) pathway and further comprising a heterologous polynucleotide encoding a non-phosphorylating NADP-dependent glyceraldehyde-3-phosphate dehydrogenase (GAPN). Also described are methods of using the recombinant yeast cells to produce 3-HP and acrylic acid.