CO-Rich Substrate Inoculation for Fermentation Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Industrial gas streams with suboptimal H2:CO molar ratios hinder cell growth, product selectivity, and stability in fermentation processes, particularly in gas fermentation for producing fuels and chemicals from CO2, CO, and H2.
Innovation Solution
A multi-stage gas fermentation process involving an inoculation reactor and bioreactors, where a CO-rich C1-containing gaseous substrate with controlled H2:CO molar ratios is used to produce an inoculum, and subsequently fermented in bioreactors to optimize biomass growth and product selectivity, employing hydrogen removal processes like pressure swing adsorption or membrane separation to adjust the substrate composition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If industrial gas streams with suboptimal H2:CO molar ratios are used directly in fermentation, then the process is simple, but cell growth, product selectivity, and stability deteriorate
Solution Approach 1:
The patent applies preliminary action by adjusting the H2:CO molar ratio of the gas substrate before it enters the fermentation reactor. A gas composition adjustment unit is positioned upstream to modify the gas composition in advance, ensuring optimal conditions for cell growth and product selectivity before fermentation begins. This preliminary adjustment resolves the contradiction by preparing the gas stream beforehand rather than dealing with suboptimal composition during fermentation.
Solution Approach 2:
The patent implements parameter changes by dynamically adjusting the H2:CO molar ratio parameter of the gas substrate. The gas composition adjustment unit modifies the physical-chemical parameters of the gas stream (specifically the molar ratio of hydrogen to carbon monoxide) to match the optimal range for microbial fermentation. This parameter optimization directly improves cell growth rate and product selectivity while maintaining a relatively simple overall process structure.
2Manufacturing precision
If gas composition is optimized for fermentation, then product selectivity improves, but process complexity increases due to hydrogen removal processes
Solution Approach 1:
The patent applies the extraction principle by removing excess hydrogen from the industrial gas stream before fermentation. A hydrogen removal unit is positioned upstream to extract and separate hydrogen from the gas mixture, adjusting the H2:CO molar ratio to the optimal range. This extraction of the problematic component (excess hydrogen) improves product selectivity by preventing unwanted side reactions while adding only a moderate level of process complexity through a dedicated gas treatment stage.
Solution Approach 2:
The patent uses an intermediary gas composition adjustment unit that acts as a mediator between the industrial gas source and the fermentation reactor. This intermediary device modifies the gas composition by removing excess hydrogen and adjusting the H2:CO molar ratio, thereby improving product selectivity without requiring direct modification of the fermentation reactor itself. The intermediary approach isolates the complexity of gas treatment from the core fermentation process.
3Stability of the object's composition
If H2:CO molar ratio is not controlled, then the process is straightforward, but long-term stability in bioreactors deteriorates
Solution Approach 1:
The patent implements feedback control by monitoring the H2:CO molar ratio of the incoming gas stream and dynamically adjusting the hydrogen removal process accordingly. Sensors detect the actual gas composition, and this information feeds back to the gas composition adjustment unit, which modifies hydrogen removal rates to maintain the optimal H2:CO ratio. This feedback mechanism ensures long-term fermentation stability by continuously adapting to variations in gas composition while maintaining a relatively simple control architecture.
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
This process enhances biomass growth rates, increases product selectivity, and improves long-term stability in downstream bioreactors, particularly for fermentation products like ethanol, by optimizing the gas composition before fermentation.
Implementation Method 1
employing hydrogen removal processes like pressure swing adsorption or membrane separation to adjust the substrate composition
Implementation Method 2
employing hydrogen removal processes like pressure swing adsorption or membrane separation to adjust the substrate composition
Implementation Method 3
C1-fixing microorganisms have been demonstrated to convert gases containing CO2, CO, and/or H2 into products such as ethanol and 2,3-butanediol
Data Source
AI summary
The invention is directed to a process for producing one or more fermentation product in a multi-stage process including an inoculation reactor and at least one bioreactor. The inoculation reactor is fed a C1-containing gaseous substrate containing a reduced amount of hydrogen. The hydrogen is reduced to increase the proportion of CO in the C1-containing gaseous substrate being provided to the inoculation reactor. The inoculation reactor ferments the CO-rich C1-containing gaseous substrate and produces an inoculum, which is fed to at least one bioreactor. The bioreactor receives the C1-containing gaseous substrate, which may or may not contain reduced amounts of hydrogen, to produce one or more fermentation product. By providing a CO-rich C1-containing gaseous substrate to the inoculation reactor, both the inoculation reactor and the subsequent bioreactor(s), are able to have increased stability and product selectivity.