Microbial Organisms Enhancing Reducing Equivalents for Adipate Production
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Solution Overview
Problem
Current methods for producing adipate, 6-aminocaproate (6-ACA), hexamethylenediamine (HMDA), and caprolactam are inefficient, as they often suffer from insufficient reducing equivalents and loss of these equivalents to byproducts, limiting product yields.
Innovation Solution
Development of non-naturally occurring microbial organisms (NNOMOs) with a methanol metabolic pathway (MMP) that enhance reducing equivalents availability, allowing for the production of adipate, 6-ACA, HMDA, and caprolactam by incorporating methanol metabolic enzymes such as methanol dehydrogenase and formaldehyde assimilation pathways.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional methods are used for producing adipate, 6-ACA, HMDA, and caprolactam, then the production process is simple, but the product yield is limited due to insufficient reducing equivalents
Solution Approach 1:
The metabolic pathway is segmented into distinct functional modules: methanol metabolic pathway (MMP) for generating reducing equivalents, and separate biosynthetic pathways for adipate, 6-ACA, HMDA, and caprolactam. This modular segmentation allows independent optimization of each pathway and facilitates the integration of exogenous enzymes to enhance reducing equivalent production without overwhelming system complexity.
Solution Approach 2:
Reducing equivalents serve as an intermediary substance that couples the methanol metabolic pathway with the biosynthetic pathways. By introducing MMP enzymes (such as methanol dehydrogenase, formaldehyde dehydrogenase) that produce reducing equivalents, the system mediates energy transfer from methanol oxidation to product synthesis, thereby increasing product yield without requiring direct modification of all biosynthetic steps.
2Productivity
If more reducing equivalents are produced to increase product yield, then productivity improves, but loss of reducing equivalents to byproducts increases
Solution Approach 1:
The system employs feedback control through metabolic regulation where the availability of reducing equivalents influences flux distribution between product formation and byproduct formation. By monitoring reducing equivalent levels, the engineered pathways ensure that excess reducing equivalents are directed toward target product synthesis rather than byproduct formation, thereby minimizing energy loss while maintaining high productivity.
Solution Approach 2:
The redox balance parameters are changed by introducing MMP enzymes that alter the NADH/NAD+ ratio and other reducing equivalent pools. This parameter change shifts the metabolic flux distribution favoring product synthesis over byproduct formation, effectively reducing reducing equivalent loss while enhancing productivity. The engineered pathways optimize the redox state to maximize carbon efficiency.
3Productivity
If methanol metabolic pathway enzymes are incorporated to enhance reducing equivalents availability, then product yield increases, but the complexity of the organism's metabolic network increases
Solution Approach 1:
The methanol metabolic pathway enzymes are designed to perform multiple functions: generating reducing equivalents, producing formaldehyde intermediates, and regulating metabolic flux. This multi-functionality reduces the need for separate dedicated pathways, thereby limiting the increase in overall metabolic network complexity while still achieving enhanced product yield through the universal role of MMP enzymes in supporting multiple biosynthetic routes.
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 use of NNOMOs with MMPs increases the yield of adipate, 6-ACA, and HMDA by providing sufficient reducing equivalents, improving the efficiency of these biochemical pathways and maximizing product yields from carbohydrate feedstocks.
Implementation Method 1
a methanol dehydrogenase (EM9); a formaldehyde dehydrogenase (EM11)
Implementation Method 2
a formaldehyde dehydrogenase (EM11)
Implementation Method 3
MMP comprises one or more enzymes selected from the group consisting of a methanol methyltransferase (EM1); a methylenetetrahydrofolate reductase (EM2); a methylenetetrahydrofolate dehydrogenase (EM3)
Data Source
AI summary
Provided herein is a non-naturally occurring microbial organism having a methanol metabolic pathway that can enhance the availability of reducing equivalents in the presence of methanol. Such reducing equivalents can be used to increase the product yield of organic compounds produced by the microbial organism, such as adipate, 6-aminocaproate, hexamethylenediamine or caprolactam. Also provided herein are methods for using such an organism to produce adipate, 6-aminocaproate, hexamethylenediamine or caprolactam.