Lactic Acid Induction of Wood-Ljungdahl Pathway for CO2 Fixation
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Solution Overview
Problem
Current methods for carbon dioxide biofixation by anaerobic organisms, such as those using the Wood-Ljungdahl pathway, require improvement in their ability to metabolize CO2 into useful chemicals and biofuels.
Innovation Solution
The use of lactic acid and/or its salts at concentrations ranging from 0.5 g/L to 3 g/L in the liquid medium for microorganisms like Clostridium aceticum and Methanobacterium thermoautotrophicum, which increases the expression of genes involved in the Wood-Ljungdahl pathway, enhancing CO2 fixation and production of acids and alcohols.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional carbon dioxide biofixation methods using anaerobic organisms are used, then CO2 can be converted into organic compounds, but the efficiency of CO2 metabolism into useful chemicals and biofuels is insufficient
Solution Approach 1:
The patent applies parameter changes by introducing lactic acid as a chemical inducer that modifies the physiological state of anaerobic organisms. Lactic acid triggers increased expression of genes involved in the Wood-Ljungdahl pathway (such as codH, cooS, and metF), thereby enhancing the organism's ability to fix CO2 and produce chemicals like acetate and ethanol. This chemical induction approach transforms the metabolic efficiency parameter without changing the fundamental biological system.
2Productivity
If the Wood-Ljungdahl pathway is used for CO2 fixation by chemoautotrophic microorganisms, then CO2 can be metabolized into organic compounds, but the ability to produce useful chemicals and biofuels needs improvement
Solution Approach 1:
The patent implements feedback control by using lactic acid as an inducer that creates a positive feedback loop. Lactic acid addition stimulates increased expression of Wood-Ljungdahl pathway genes, which enhances CO2 fixation capacity and chemical production. The system responds to lactic acid presence by upregulating metabolic pathways, creating a self-reinforcing mechanism that improves both productivity and reliability of CO2 conversion.
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 induces a 1.5-fold or more increase in gene expression, leading to improved carbon capture and production of acids and alcohols, specifically acetic acid and ethanol, demonstrating enhanced CO2 fixation efficiency.
Implementation Method 1
the use of lactic acid and/or salts thereof for inducing 1.5 fold or more increase, relative to the microorganism cultured without the presence of lactic acid and/or salts thereof, of at least one gene chosen from codH, codH beta, codH delta, codH gamma, coos 1, and metF
Implementation Method 2
A major non-photosynthetic carbon dioxide fixation pathway used by chemoautotrophic microorganisms is the Wood-Ljungdahl (WL) pathway
Implementation Method 3
allowing the microorganism to produce at least one product chosen from acids and alcohols
Data Source
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AI summary
At least one product chosen from acids and alcohols is produced by a microbial fermentation process comprising: providing a gaseous substrate and a liquid medium to a microorganism, wherein the liquid medium comprises lactic acid and/or salts thereof, and wherein the gaseous substrate comprises at least one carbon source chosen from CO and CO2, and allowing the microorganism to produce at least one product chosen from acids and alcohols.