Novel Carbon Dioxide Fixation Cycle Enzymes
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Solution Overview
Problem
Conventional carbon dioxide fixation cycles are inefficient, requiring high ATP consumption and lacking in energy conversion efficiency, which limits their application in producing carbonaceous products.
Innovation Solution
A novel carbon dioxide fixation cycle comprising four enzymes - succinyl-CoA synthetase, 2-oxoglutarate synthase, isocitrate dehydrogenase, and isocitrate lyase - that operates in vitro, utilizing only ATP and NADPH as biochemical energy, reducing ATP consumption to three molecules per carbon dioxide molecule, thereby enhancing energy conversion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional carbon dioxide fixation cycles (Calvin cycle, reductive citric acid cycle, etc.) are used, then carbon dioxide fixation can be achieved, but high ATP consumption and low energy conversion efficiency occur
Solution Approach 1:
The invention segments the carbon dioxide fixation process into distinct enzymatic steps using a specific sequence of four enzymes (2-oxoglutarate synthase, isocitrate dehydrogenase, isocitrate lyase, and succinyl-CoA synthetase). This segmentation allows optimization of each step's energy efficiency, achieving lower overall ATP consumption compared to conventional cycles while maintaining productive carbon fixation output.
2Loss of energy
If ATP consumption is reduced to enhance energy efficiency, then energy conversion efficiency improves, but carbon dioxide fixation capability may be compromised
Solution Approach 1:
The invention changes the biochemical parameters of the carbon fixation cycle by using a specific enzymatic sequence that alters the energy investment pattern. The cycle uses only 3 ATP molecules per 2 CO2 fixed, compared to higher consumption in conventional cycles, while maintaining reliable carbon dioxide fixation capability through the coordinated action of the four enzymes in the specified sequence.
3Productivity
If more ATP and NADPH are consumed, then more carbonaceous products can be produced, but energy efficiency decreases
Solution Approach 1:
The invention establishes a continuous cyclic process where the four enzymes work in sequence to continuously fix carbon dioxide and produce carbonaceous products. The cycle regenerates substrates continuously (isocitrate → succinate + glyoxylate → succinyl-CoA → 2-oxoglutarate → isocitrate), maintaining productive action while minimizing energy input requirements at each step, thereby achieving high productivity with high energy efficiency.
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 novel cycle achieves approximately 2.5 times higher energy conversion efficiency compared to the Calvin cycle, allowing for continuous carbohydrate production without additional substrates and enabling efficient carbon dioxide fixation.
Implementation Method 1
A novel carbon dioxide fixation cycle comprising four enzymes - succinyl-CoA synthetase, 2-oxoglutarate synthase, isocitrate dehydrogenase, and isocitrate lyase
Data Source
AI summary
The present invention relates to a novel carbon dioxide fixation cycle synthesizing a carbohydrate product from carbon dioxide in vitro. In addition, the present invention relates to a unit or a composition carrying out carbon dioxide fixation in cyclic manner. Additionally, the present invention relates to a method to fix carbon dioxide or a method to produce glyoxylate from the carbon dioxide fixation cycle. The present carbon dioxide fixation cycle is not found in natural world, and we found that, when the novel carbon dioxide fixation cycle is used, only three ATP molecules are consumed to fix one carbon dioxide molecule, and thus novel carbon dioxide fixation cycle has an energy conversion efficiency approximately 2.5 times higher than that of the Calvin cycle.