Two-Stage Acetate Fermentation for CO2 Conversion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current gas fermentation technologies face challenges in efficiently converting carbon dioxide and hydrogen into sustainable fuels and chemicals, limiting their potential to significantly displace fossil fuel use and reduce greenhouse gas emissions.
Innovation Solution
A two-stage fermentation process is employed, where a primary fermentation converts gas to acetate using Wood-Ljungdahl pathway-expressing microorganisms, and a secondary fermentation converts acetate into target products using different microorganisms, with integrated systems for nutrient and gas recycling to enhance efficiency and reduce emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If gas fermentation technology is used to convert CO2 and H2 into sustainable fuels and chemicals, then greenhouse gas emissions are reduced and fossil fuel dependence decreases, but technical challenges limit efficiency and productivity
Solution Approach 1:
The fermentation process is divided into two separate stages performed by different microorganisms: (1) acetate production from gaseous substrates using Wood-Ljungdahl pathway microorganisms, and (2) conversion of acetate to target products using secondary microorganisms. This segmentation allows each stage to be optimized independently, resolving the contradiction between emission reduction and conversion efficiency.
Solution Approach 2:
Acetate serves as an intermediary substance that bridges the first fermentation stage (CO2/H2 to acetate) and the second fermentation stage (acetate to target products). This intermediary approach enables efficient coupling of two specialized biological systems, overcoming the limitations of single-organism gas fermentation while maintaining high conversion efficiency.
2Productivity
If a two-stage fermentation process is used to improve conversion efficiency, then productivity increases, but device complexity increases
Solution Approach 1:
The patent combines two fermentation systems into an integrated process where the output of the first fermentation (acetate) directly feeds into the second fermentation. By merging the two stages through substrate coupling and implementing integrated nutrient recycling, the system achieves high productivity while managing complexity through unified process design.
Solution Approach 2:
The system recovers and recycles nutrients from the fermentation broths back into the process, converting waste streams into valuable resources. This recovery approach reduces the need for additional input materials and simplifies the overall system by eliminating waste disposal steps, thereby increasing productivity without proportionally increasing device complexity.
3Manufacturing precision
If different microorganisms are used in each fermentation stage to optimize product formation, then manufacturing precision improves, but ease of manufacture decreases
Solution Approach 1:
The patent employs microorganisms with complementary metabolic capabilities where each strain is specialized for its specific function: Wood-Ljungdahl pathway microorganisms for acetate production from gases, and secondary microorganisms for diverse target product synthesis from acetate. This multi-functional approach allows precise control over product formation while using well-characterized, commercially available microbial strains that simplify manufacturing implementation.
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 approach enables the production of sustainable fuels and chemicals, potentially displacing 30% of crude oil use and reducing global CO2 emissions by 10%, while optimizing resource utilization and reducing operational costs.
Implementation Method 1
The first microorganism expresses the enzymes of the Wood-Ljungdahl pathway. The gaseous substrate is anaerobically fermented to produce acetate as a first product
Implementation Method 2
Fermenting the first product produces at least a first target product in a second fermentation broth
Data Source
AI summary
The disclosure relates to the combination of a primary fermentation that converts gas to acetate with a secondary fermentation that converts acetate to a target product. Preferably, the gas contains carbon dioxide, such that the disclosure enables the fixation of carbon dioxide into useful products. The fermentations may be any combination of aerobic and anaerobic, batch and continuous. The fermenting microorganisms may typically be bacterial or fungal.