Microbial Strain Gallic Acid Production with Selective Hydroxylase

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Solution Overview

Problem

Existing methods for producing gallic acid from protocatechuic acid are inefficient, as no enzyme is known to selectively convert protocatechuic acid into gallic acid, leading to imbalanced production ratios and high costs due to unstable plant-derived raw material supplies.

Innovation Solution

Utilizing a protocatechuic acid 5-hydroxylase derived from Comamonadaceae family microorganisms or proteins with 70% amino acid sequence identity for efficient conversion of protocatechuic acid into gallic acid, integrated into microbial strains through genetic engineering.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If p-hydroxybenzoate hydroxylase (PobA) is used to produce protocatechuic acid from p-hydroxybenzoic acid, then protocatechuic acid production is achieved, but the ratio of gallic acid to protocatechuic acid is not increased sufficiently because the reaction for producing protocatechuic acid advances dominantly over the reaction for producing gallic acid

Engineering Contradiction:
Improvegallic acid production efficiencyVSAvoidgallic acid to protocatechuic acid ratio
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent divides the gallic acid production pathway into two distinct enzymatic steps: first, p-hydroxybenzoate hydroxylase converts p-hydroxybenzoic acid to protocatechuic acid; second, protocatechuic acid 5-hydroxylase converts protocatechuic acid to gallic acid. This segmentation allows each enzyme to perform its specific function optimally, ensuring both protocatechuic acid and gallic acid are produced in sufficient quantities with improved selectivity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces protocatechuic acid 5-hydroxylase as an intermediary enzyme that bridges the gap between protocatechuic acid production and gallic acid formation. This intermediary enzyme enables the conversion of the intermediate product (protocatechuic acid) into the final product (gallic acid), solving the bottleneck where protocatechuic acid accumulated without sufficient conversion to gallic acid.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Quantity of substance

If plant raw materials such as galls are used for gallic acid production, then gallic acid can be produced, but the supply amount per harvest is not stable causing price increase

Engineering Contradiction:
Improvegallic acid supply stabilityVSAvoidproduction cost
Core Design Contradiction:
Quantity of substanceVSProductivity

Solution Approach 1:

The patent employs microbial cells (such as Escherichia coli) as self-service factories that can autonomously convert inexpensive substrates like glucose into gallic acid through the introduced enzymatic pathway. The microorganisms take up glucose from the medium, process it through the metabolic pathway involving p-hydroxybenzoate hydroxylase and protocatechuic acid 5-hydroxylase, and produce gallic acid continuously, eliminating dependence on unstable plant raw material harvests.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent changes the production system from plant-based extraction to microbial fermentation, fundamentally altering the substrate parameter from plant-derived galls to sugar-based media. This parameter change enables stable, year-round production using inexpensive, readily available carbon sources like glucose, thereby stabilizing supply and reducing costs.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If chemical synthesis methods are used for gallic acid production, then production efficiency is high, but environmental burden increases due to use of organic solvents, heavy metals, strong acids and strong alkalis

Engineering Contradiction:
Improveproduction efficiencyVSAvoidenvironmental burden
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces chemical synthesis mechanisms with biological catalysis. Instead of using chemical reagents, organic solvents, heavy metals, strong acids, and strong alkalis, the invention utilizes microbial cells equipped with specific enzymes (p-hydroxybenzoate hydroxylase and protocatechuic acid 5-hydroxylase) to catalyze the conversion of glucose to gallic acid. This substitution eliminates harmful chemical substances while maintaining production efficiency.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent uses microorganisms as temporary, disposable biocatalysts that can be cultured, used for fermentation, and then discarded or recycled. These microbial systems provide a sustainable alternative to persistent chemical reagents, enabling efficient gallic acid production without the environmental persistence and toxicity associated with traditional chemical synthesis materials.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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

The microbial strains significantly improve gallic acid yield and production efficiency, stabilizing supply and reducing costs by leveraging the enzymatic activity of protocatechuic acid 5-hydroxylase.

Implementation Method 1

a protocatechuic acid 5-hydroxylase derived from a microorganism of the family Comamonadaceae or a protein having an identity of 70% or more with the amino acid sequence of the protocatechuic acid 5-hydroxylase

Methodology Applied
Scientific EffectEnzymatic hydroxylation: Enzyme

Implementation Method 2

a production method through microbial fermentation using sugar or the like as the substrate

Methodology Applied
Scientific EffectFermentation: Fermentation

Data Source

PatentEP4600344A1Microbial strain, protein, and method for producing gallic acid using microbial strain or protein
Publication Date: 2025.08.13 UNIV OF TSUKUBA
  • EP4600344A1 patent drawingFigure 1~2
  • EP4600344A1 patent drawingFigure 3
  • EP4600344A1 patent drawing

AI summary

An object of the present technology is to provide a protein having protocatechuic acid 5-oxidization activity which can produce gallic acid from protocatechuic acid efficiently and a microbial strain which expresses the protein. Using a protocatechuic acid 5-hydroxylase derived from a microorganism of the genus Comamonas or a protein having an identity of 70% or more with the amino acid sequence of the protocatechuic acid 5-hydroxylase, gallic acid can be produced efficiently from protocatechuic acid. Moreover, through fermentation using a microbial strain obtained by introducing a gene encoding the enzyme, gallic acid can be produced from protocatechuic acid.