Low-Temperature Fermentation for CO2-to-PHA Fatty Acid Production

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Solution Overview

Problem

The production of biodegradable polymers like polyhydroxyalkanoates (PHAs) is limited by their brittleness and competition with food production for raw materials, and current recycling methods are inefficient, leading to significant plastic waste and high production costs due to the use of volatile fatty acids.

Innovation Solution

A method involving microbial biomass expressing the Wood-Ljungdahl pathway enzymes is used to produce short-chain fatty acids under anaerobic conditions with CO2 and H2, suppressing methane production and enhancing the production of valeric acid, isovaleric acid, and hexanoic acid at low temperatures, which are then polymerized to form polyhydroxyalkanoates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If PHAs are produced from starch or lipids, then production is achieved, but it competes with food production for raw materials

Engineering Contradiction:

ImprovePHA productionVSAvoidcompetition with food production

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The invention changes the substrate parameter from starch/lipids to gaseous substrates (CO and CO2), fundamentally altering the raw material source to eliminate competition with food production while maintaining PHA production capability

Inventive Principle:

Principle #35Parameter changes

2Productivity

If volatile fatty acids are added to produce PHAs, then production is achieved, but the price increases substantially

Engineering Contradiction:

ImprovePHA productionVSAvoidproduction cost

Core Design Contradiction:

ProductivityVSEase of manufacture

Solution Approach 1:

The invention uses cheap gaseous substrates (CO and CO2) instead of expensive volatile fatty acids as the carbon source for PHA production, significantly reducing raw material costs while maintaining production efficiency

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Productivity

If PHB is produced from methane using mixed cultures, then production is achieved, but the product is brittle and usability is limited

Engineering Contradiction:

ImprovePHB productionVSAvoidbrittleness

Core Design Contradiction:

ProductivityVSStrength

Solution Approach 1:

The invention produces PHAs with different local compositions by controlling fermentation conditions, creating polymers with varying monomer ratios (3-hydroxyvalerate, 3-hydroxybutyrate, 3-hydroxyhexanoate) that balance mechanical properties and reduce brittleness

Inventive Principle:

Principle #3Local quality

4Quantity of substance

If low temperature fermentation is used to produce short-chain fatty acids, then methane production is suppressed and fatty acid yield increases, but production time may increase

Engineering Contradiction:

Improveshort-chain fatty acid yieldVSAvoidproduction time

Core Design Contradiction:

Quantity of substanceVSLoss of time

Solution Approach 1:

The invention optimizes temperature as a critical parameter, operating at low temperatures (15-45°C, preferably 20-35°C) to suppress methane production while maintaining high short-chain fatty acid yields, and uses enriched microbial biomass to accelerate the fermentation process

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 enables the production of biodegradable polymers from waste materials, reducing production costs and overcoming the limitations of traditional PHA production by increasing the yield of valuable fatty acids and suppressing methane formation.

Implementation Method 1

providing a microbial biomass comprising at least one microorganism expressing the enzymes of the Wood-Ljungdahl pathway; growing the microbial biomass under anaerobic conditions comprising carbon dioxide and hydrogen gas to form an enriched microbial biomass; producing a fermentation product comprising at least one short-chain fatty acid by using the enriched microbial biomass

Methodology Applied

Scientific EffectWood-Ljungdahl pathway:

Implementation Method 2

growing the microbial biomass under anaerobic conditions comprising carbon dioxide and hydrogen gas to form an enriched microbial biomass; producing a fermentation product comprising at least one short-chain fatty acid by using the enriched microbial biomass

Methodology Applied

Scientific EffectFermentation: Fermentation

Data Source

PatentEP4663764A1A fermentation product and a method for producing a fermentation product

Publication Date: 2025.12.17 NG NORDIC FINLAND OY

AI summary

According to an example aspect of the present invention, there is provided a method comprising the steps of providing a microbial biomass comprising at least one microorganism expressing the enzymes of the Wood-Ljungdahl pathway; growing the microbial biomass under anaerobic conditions comprising carbon dioxide and hydrogen gas to form an enriched microbial biomass; producing a fermentation product comprising at least one short-chain fatty acid by using the enriched microbial biomass; wherein the producing step is performed at a temperature below 18°C.