Redox Potential Control for Anaerobic Bioproduction of Long Chain Organic Acids

Solution Overview

Problem

Bioremediation of TNT contamination by aerobic microorganisms is problematic due to the formation of toxic and mutagenic degradation intermediates, while anaerobic pathways avoid these issues but require effective methods to produce industrially valuable longer carbon feedstocks.

Innovation Solution

Adding a redox active compound with a specific redox potential to anaerobic microbial cultures, such as Clostridium, to divert redox potential and enhance production of longer chain length acids like butyric acid, using compounds like trinitrotoluene or phenazine-1 carboxylic acid, which shift metabolism away from hydrogen formation and towards reduction of TNT, thereby producing more valuable chemicals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If aerobic biodegradation pathways are used to degrade TNT, then degradation occurs, but toxic and mutagenic degradation intermediates are formed

Engineering Contradiction:

Improvedegradation effectivenessVSAvoidtoxicity of degradation intermediates

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent changes the redox potential parameter of the culture medium by adding electron carriers with specific redox potentials (between -0.116 and -0.253 V) to shift the metabolic pathways of anaerobic microorganisms. This parameter change redirects electron flow away from hydrogen formation toward the reduction of TNT and production of longer chain organic acids, achieving both degradation and valuable product formation without toxic intermediates

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent introduces electron carriers (intermediaries) with specific redox potentials as mediators in the metabolic process. These electron carriers, such as phenazine-1-carboxylic acid or trinitrotoluene itself at controlled potentials, act as intermediaries to transfer electrons from the microbial metabolism to TNT reduction, enabling the production of longer chain organic acids while avoiding toxic intermediate formation

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-generated harmful factors

If anaerobic degradation pathways are used to avoid toxic intermediates, then safer degradation occurs, but production of longer chain organic acids is limited

Engineering Contradiction:

Improvetoxicity reductionVSAvoidproduction of longer chain organic acids

Core Design Contradiction:

Object-generated harmful factorsVSProductivity

Solution Approach 1:

The patent changes the redox potential parameter of the culture medium by adding electron carriers with specific redox potentials (between -0.116 and -0.253 V) to shift the metabolic pathways of anaerobic microorganisms. This parameter change redirects electron flow away from hydrogen formation toward the reduction of TNT and production of longer chain organic acids, achieving both degradation and valuable product formation without toxic intermediates

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent maintains an anaerobic (inert oxygen-free) environment that is naturally safer and prevents the formation of toxic intermediates associated with aerobic degradation. Within this inert anaerobic atmosphere, the addition of electron carriers with specific redox potentials enhances the production of longer chain organic acids by redirecting metabolic flux without introducing oxygen-dependent toxic pathways

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

3Productivity

If redox potential is diverted to produce longer chain acids, then industrial value increases, but hydrogen formation decreases

Engineering Contradiction:

Improveproduction of longer chain organic acidsVSAvoidhydrogen production

Core Design Contradiction:

ProductivityVSQuantity of substance

Solution Approach 1:

The patent changes the redox potential parameter of the culture medium by adding electron carriers with specific redox potentials (between -0.116 and -0.253 V) to shift the metabolic pathways of anaerobic microorganisms. This parameter change redirects electron flow away from hydrogen formation toward the reduction of TNT and production of longer chain organic acids, achieving both degradation and valuable product formation without toxic intermediates

Inventive Principle:

Principle #35Parameter changes

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 effectively drives the production of longer chain organic acids, making them more industrially valuable and reducing the toxicity associated with TNT degradation intermediates, while being applicable to various anaerobic microorganisms with ferredoxin-based hydrogenases.

Implementation Method 1

Adding a redox active compound with a specific redox potential to anaerobic microbial cultures, such as Clostridium, to divert redox potential and enhance production of longer chain length acids

Methodology Applied

Scientific EffectRedox reactions: Redox Reactions

Data Source

PatentUS9856499B2Long chain organic acid bioproduction

Publication Date: 2018.01.02 WILLIAM MARCH RICE UNIVERSITY

AI summary

Method of cell culture, comprising adding a redox active compound with a redox potential of between −0.116 to −0.253 to a culture capable of forming hydrogen via a hydrogenase so that the redox potential is diverted from hydrogen to form a longer chain acids, e.g., butryic acid.