Acetogenic Cell Cat3 Expression for Higher Alcohol Production
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Solution Overview
Problem
Current methods for producing higher alcohols like butanol are limited by mass transfer issues, lower productivity, and higher energy costs due to reliance on petroleum-based or corn-based sources, which are environmentally damaging and inefficient.
Innovation Solution
A genetically modified acetogenic microbial cell with increased expression of butyryl-CoA: acetate CoA transferase (cat3) is used to convert CO and CO2 into higher alcohols, enabling efficient production from sustainable carbon sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If petroleum-based or corn-based methods are used for higher alcohol production, then current production capability is maintained, but environmental damage increases and energy costs rise
Solution Approach 1:
The invention changes the fundamental parameter of carbon source from petroleum/corn-based materials to gaseous substrates (CO, CO2, H2). This parameter change enables direct conversion to higher alcohols through engineered metabolic pathways, eliminating the need for agricultural cultivation, starch processing, and traditional fermentation steps, thereby reducing environmental damage while maintaining productivity
Solution Approach 2:
The invention introduces an intermediary acetic acid fermentation step that converts gaseous substrates into acetic acid, which then serves as a precursor for higher alcohol production. This intermediary approach allows the system to bridge the gap between gaseous carbon sources and liquid alcohol products, solving the mass transfer and productivity issues associated with direct gas-to-alcohol conversion
2Productivity
If cornstarch-based fermentation process is used, then butanol production is achieved, but energy consumption approaches the energy value of the product
Solution Approach 1:
The invention fundamentally changes the substrate parameter from solid cornstarch to gaseous CO/CO2/H2 mixtures. This enables direct carbon fixation and conversion through the acetic acid pathway, eliminating energy-intensive steps including corn cultivation, harvesting, starch processing, and multiple fermentation stages, thereby reducing energy consumption to well below the energy value of the butanol product
Solution Approach 2:
The invention extracts and eliminates the energy-consuming intermediate steps from the traditional cornstarch-to-butanol pathway. By removing agricultural cultivation, starch processing, and complex fermentation sequences, the system achieves direct conversion from gaseous substrates to butanol through a simplified acetic acid intermediary pathway, dramatically reducing overall energy consumption
3Productivity
If Alfol® Alcohol Process is used with organoaluminium catalyst, then higher alcohols are produced from ethylene, but a wide spectrum of alcohols is yielded limiting specific product production
Solution Approach 1:
The invention applies local quality by engineering specific metabolic pathways within the acetic acid producing cells that are tailored to produce particular higher alcohols. By modifying specific enzymes and metabolic routes in the biological system, the process achieves site-specific control over product distribution, enabling selective production of desired higher alcohols rather than a broad spectrum mixture
Solution Approach 2:
The invention introduces dynamics by enabling flexible adjustment of product specificity through genetic engineering. The metabolic pathway can be dynamically configured by expressing different enzyme combinations or modifying pathway flux, allowing the system to adapt and optimize for specific higher alcohol products based on market demand without being constrained by a fixed catalyst distribution pattern
4Adaptability or versatility
If gaseous substrates are used in current methods, then carbon source availability is improved, but mass transfer into fermentation broth is limited
Solution Approach 1:
The invention introduces an intermediary acetic acid fermentation step that serves as a bridge between gaseous substrates and higher alcohol production. The acetic acid pathway acts as an intermediary metabolic route that efficiently incorporates gaseous carbon sources into soluble intermediates, which then feed into higher alcohol synthesis, thereby overcoming mass transfer limitations while maintaining productivity
Solution Approach 2:
The invention establishes continuity of useful action by creating an integrated two-stage process where acetic acid production continuously feeds into higher alcohol synthesis. The gaseous substrates are continuously converted to acetic acid, which is immediately utilized as a precursor for higher alcohol production, eliminating idle time and maintaining continuous productive action throughout the system
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 modified cell significantly enhances higher alcohol production, achieving higher yields and reducing energy costs by utilizing CO and CO2, thus providing a more sustainable and efficient production method.
Implementation Method 1
the cell is genetically modified to express a butyryl-CoA: acetate CoA transferase (cat3)
Implementation Method 2
A genetically modified acetogenic microbial cell with increased expression of butyryl-CoA: acetate CoA transferase (cat3) is used to convert CO and CO2 into higher alcohols
Data Source
Figure 1
AI summary
There is provided an acetogenic microbial cell which is capable of producing at least one higher alcohol from a carbon source, wherein the acetogenic microbial cell is genetically modified to comprise an increased expression relative to its wild type cell of at least one enzyme, E8, a butyryl-CoA: acetate CoA transferase (cat3). There is also provided a method and use of the cell to produce higher alcohols.