Oxygen-Tolerant Enzyme Process for Formate Production
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional hydrogenase and formate dehydrogenase enzymes are inhibited by trace amounts of oxygen, limiting the conversion of hydrogen into formate from various hydrogen sources, especially cheap and sustainable sources like coke oven gas, due to their low selectivity and efficiency and requirement for precious metals.
Innovation Solution
A process involving oxygen-tolerant hydrogenase and formate dehydrogenase enzymes, mixed with a gas containing hydrogen, carbon dioxide, and NAD+, which allows for the production of formate even in the presence of oxygen, using enzymes derived from specific strains such as Ralstonia eutropha and Rhodobacter capsulatus, and adjusting the enzyme ratio to enhance formate production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional hydrogenase and formate dehydrogenase are used, then formate production is achieved, but the enzymes are inhibited by trace oxygen, limiting application to oxygen-free hydrogen sources
Solution Approach 1:
The patent changes the biochemical parameters of the enzymes by selecting specific oxygen-tolerant variants (hydrogenase from Ralstonia eutropha and formate dehydrogenase from Rhodobacter capsulatus) that have different oxygen sensitivity characteristics compared to conventional enzymes. This parameter change enables the enzymatic system to function reliably in the presence of trace oxygen up to 1.7%, expanding adaptability to various hydrogen sources including coke oven gas
Solution Approach 2:
The patent introduces an intermediary substance (formate dehydrogenase enzyme) that mediates the conversion of CO2 to formate using electrons from hydrogen oxidation. This intermediary enables the system to tolerate oxygen by providing an alternative electron pathway that is less sensitive to oxygen inhibition, allowing the use of mixed gas sources containing both oxygen and hydrogen
2Adaptability or versatility
If synthetic catalysts are used for hydrogen oxidation and CO2 reduction, then various hydrogen sources can be utilized, but selectivity and efficiency are low and precious metals are required
Solution Approach 1:
The patent replaces expensive precious metal-based synthetic catalysts with inexpensive biological enzymes that can be produced through fermentation. The enzymes from Ralstonia eutropha and Rhodobacter capsulatus are cost-effective alternatives that maintain high catalytic activity without requiring rare metals, making the process economically viable
Solution Approach 2:
The patent changes the catalytic parameters by using enzymatic catalysts with specific active sites optimized for hydrogen oxidation and CO2 reduction. These enzymes provide higher selectivity and efficiency compared to synthetic catalysts, achieving superior conversion rates while being compatible with various hydrogen sources including those containing trace oxygen
3Ease of manufacture
If conventional enzymes are used with cheap hydrogen sources containing oxygen, then cost is reduced, but the enzymes are irreversibly damaged by trace oxygen
Solution Approach 1:
The patent changes the oxygen tolerance parameter of the enzymatic system by selecting specific enzyme variants that have evolved or been engineered to withstand oxygen exposure. The hydrogenase from Ralstonia eutropha and formate dehydrogenase from Rhodobacter capsulatus possess inherent oxygen tolerance that allows them to maintain activity in the presence of up to 1.7% oxygen, enabling the use of inexpensive industrial hydrogen sources
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
Enables the production of formate with high volumetric energy capacity while maintaining molar energy capacity, utilizing hydrogen sources containing oxygen, and allows for the reuse of enzymes without activity loss, effectively converting hydrogen and carbon dioxide into formate without by-products.
Implementation Method 1
The oxidation of H2 and reduction of CO2 may occur in hydrogenase (H2ase) and formate dehydrogenase (FDH), respectively
Implementation Method 2
The oxidation of H2 and reduction of CO2 may occur in hydrogenase (H2ase) and formate dehydrogenase (FDH), respectively
Implementation Method 3
preparing a mixed enzyme by mixing hydrogenase (H2ase) with oxygen tolerance and formate dehydrogenase (FDH) with oxygen tolerance
Data Source
AI summary
In a process for producing formate, a mixed enzyme by mixing hydrogenase (H2ase) with oxygen tolerance and formate dehydrogenase (FDH) with oxygen tolerance is prepared, and the mixed enzyme and a gas including H2, CO2 and NAD+ are mixed such that formate may be produced even in the presence of oxygen, and thereby utilizing hydrogen sources including oxygen, such as coke oven gas.