Genetically Modified Acetogen for Ethanol Production
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Solution Overview
Problem
Acetogenic microorganisms producing multiple products during microbial fermentation, such as ethanol and 2,3-butanediol, face efficiency and yield reductions due to carbon diversion, toxicity, and contamination issues, making it difficult to control fermentation conditions and recover desired products.
Innovation Solution
Genetically modified carboxydotrophic acetogenic microorganisms with disrupted 2,3-butanediol biosynthesis pathways to produce ethanol as the main product with reduced 2,3-butanediol production, utilizing genetic modifications that inhibit enzymes involved in 2,3-butanediol production, such as acetolactate synthase, acetolactate decarboxylase, and 2,3-butanediol dehydrogenase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If acetogenic microorganisms are used to produce multiple products during fermentation, then product diversity is improved, but production efficiency and yield of the main desired product deteriorate due to carbon diversion
Solution Approach 1:
The patent extracts and removes the 2,3-butanediol biosynthesis pathway from the microorganism through genetic modification (gene knockout). By eliminating the enzymes acetolactate synthase, acetolactate decarboxylase, and 2,3-butanediol dehydrogenase, the microorganism can no longer produce 2,3-butanediol, thereby preventing carbon diversion and improving ethanol production efficiency and yield
2Adaptability or versatility
If multiple products are produced during fermentation, then metabolic pathway versatility is improved, but product recovery and separation difficulty increases
Solution Approach 1:
The patent removes the 2,3-butanediol production pathway through genetic modification, eliminating one of the multiple products. This simplifies the fermentation broth composition to primarily ethanol and other byproducts, making product recovery and separation easier and more cost-effective
3Adaptability or versatility
If 2,3-butanediol is produced as a byproduct, then metabolic flexibility is improved, but toxicity to the microorganism increases
Solution Approach 1:
The patent eliminates the 2,3-butanediol biosynthesis pathway through gene knockout, removing the source of toxicity. By deleting the genes encoding acetolactate synthase, acetolactate decarboxylase, and 2,3-butanediol dehydrogenase, the microorganism no longer produces this toxic byproduct, thereby improving microbial health and fermentation performance
4Quantity of substance
If 2,3-butanediol is produced during fermentation, then carbon utilization is improved, but contamination risk increases as it serves as substrate for undesirable organisms
Solution Approach 1:
The patent removes the 2,3-butanediol production pathway through genetic modification, eliminating the byproduct that serves as a substrate for contaminating organisms. This prevents contamination while the microorganism maintains efficient carbon utilization for ethanol production through the Wood-Ljungdahl pathway
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
Increased ethanol production efficiency and yield, reduced toxicity, and simplified product recovery by eliminating 2,3-butanediol, which also eliminates contamination risks and reduces the need for supplementation with valine, leucine, and other amino acids, while producing additional valuable compounds like formate, lactate, and succinate.
Implementation Method 1
production of chemical compounds, particularly but not exclusively ethanol, by microbial fermentation
Implementation Method 2
one or more genetic modification which disrupts the expression and/or activity of one or more enzyme capable of converting pyruvate to acetolactate
Data Source
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AI summary
The invention relates to methods for the production of chemical compounds, particularly but not exclusively ethanol, by microbial fermentation. Also described are genetically modified micro-organisms capable of using carbon monoxide to produce one or more products, particularly but not exclusively ethanol as a main product, and producing a reduced amount or substantially no 2,3-butanediol and/or a precursor thereof.