Anaerobic Methanogen Conversion of Dilute DIC to Separable Methane

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Solution Overview

Problem

The removal of anthropogenically emitted CO2 from the atmosphere is thermodynamically expensive due to its dilute concentration in air, and existing methods for capturing and processing CO2 into stable forms are inefficient for long-term sequestration.

Innovation Solution

Utilizing anaerobic methanogens, particularly alkalotolerant hydrogenotrophic methanogens like Methanococcus vannielii, to convert dissolved inorganic carbon (DIC) in alkaline solutions into methane, which can be readily separated and stored, bypassing the need for costly separation and sorbent regeneration steps.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If CO2 is captured from the atmosphere using alkaline solution to form DIC, then the concentration of carbon is increased, but further processing is required to keep the carbon sequestered over long time periods

Engineering Contradiction:

ImproveDIC concentrationVSAvoidlong-term sequestration

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent changes the chemical parameter of DIC by converting it from a stable dissolved form into methane gas through microbial metabolism. This parameter change transforms the carbon from a state requiring further processing into a stable, low-solubility gas that can be easily separated and stored, resolving the contradiction between concentration increase and long-term sequestration reliability

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent utilizes phase transition by converting dissolved inorganic carbon (aqueous phase) into methane gas (gas phase) through anaerobic microbial metabolism. The methane then separates from the alkaline solution due to its low solubility, providing reliable long-term storage. This phase transition resolves the contradiction by creating a physically separable, stable carbon form

Inventive Principle:

Principle #36Phase transitions

2Reliability

If conventional methods are used to process DIC into stable carbon forms, then carbon can be stored, but the process is thermodynamically expensive and inefficient

Engineering Contradiction:

Improvecarbon storage stabilityVSAvoidprocessing energy cost

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent employs self-service by utilizing anaerobic microbes that naturally metabolize DIC into methane under ambient conditions. The microbial system performs the conversion autonomously without requiring external energy input, heat, or pressure changes, thereby achieving reliable carbon storage with minimal energy expenditure and resolving the contradiction between storage stability and processing energy cost

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent replaces mechanical/thermal processing systems with a biological system. Instead of using energy-intensive mechanical separation or thermal treatment methods, the invention uses anaerobic microbial metabolism to convert DIC to methane, which then separates naturally due to phase transition and low solubility. This substitution resolves the contradiction by eliminating the need for expensive processing while maintaining storage reliability

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 method achieves efficient conversion of atmospheric CO2 into methane at ambient temperatures and pressures, overcoming thermodynamic challenges and providing a stable, low-solubility product that can be easily stored and utilized for energy production.

Implementation Method 1

As a result of this physical-chemical equilibrium, DIC concentration (cDIC) in slightly alkaline aqueous solution, including of seawater, (pH 8.1) is ̃50× higher than the average CO2 concentration in air

Methodology Applied

Scientific EffectPhysical-chemical equilibrium: Absorption (physical)

Implementation Method 2

anaerobic methanogens, e.g. alkalitolerant hydrogenotrophic methanogens such as members of the Methanopyrales, Methanococcales, and Methanobacteriales

Methodology Applied

Scientific EffectAnaerobic metabolism: Anaerobic Digestion

Implementation Method 3

alkalotolerant hydrogenotrophic methanogens... can metabolize dissolved inorganic carbon (DIC), e.g. in the form of bicarbonate in sea water, at low, including atmospheric, concentration, and convert to more reduced compounds such as methane

Methodology Applied

Scientific EffectHydrogenotrophic conversion: Hydrogenation

Data Source

PatentUS20250207156A1Anaerobic microorganism metabolism for capture of dilute carbon dioxide and conversion to reduced, including self-separating, carbon compounds

Publication Date: 2025.06.26 THE BOARD OF TRUSTEES OF THE LELAND STANFORD JUNIOR UNIV

AI summary

Integrated systems and methods are provided for non-photosynthetic microbial conversion of low concentrations of dissolved inorganic carbon (DIC), including from alkaline solutions, to capture, concentrate, and store CO2 as methane (CH4) biogas or any other reduced organic compound. The methods allow CO2 capture and conversion, and can provide a source of hydrocarbons for synthesis, energy generation, carbon storage, and the like. The methods disclosed herein produce end products at high selectivity relative to chemical catalysis systems.