Calcium Borogluconate Complex in Apxl Fermentation

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Solution Overview

Problem

Current methods for producing RTX-toxin Apxl during bacterial fermentation face challenges due to calcium salt precipitation, leading to reduced yields and complications in downstream processing, especially in media lacking animal-derived components.

Innovation Solution

Incorporating borogluconate into the culturing medium to form a calcium borogluconate complex, which prevents calcium ion precipitation while maintaining their availability for bacterial transcriptional activity, combined with optimizing medium composition and increasing carbon dioxide levels during fermentation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If calcium salt is added to the culturing medium to enhance Apxl production, then transcriptional activity of the Apxl operon is enhanced and high levels of Apxl can be provided, but calcium salt precipitation occurs leading to reduced yields and complications in downstream processing

Engineering Contradiction:

ImproveApxl production yieldVSAvoiddownstream processing reliability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent employs complexing agents (such as EDTA, citrate, or phosphate buffers) as intermediary substances that bind to calcium ions in the culturing medium. These complexing agents prevent calcium salt precipitation by forming soluble calcium complexes, thereby maintaining calcium availability for transcriptional activity while eliminating precipitation-related downstream processing complications. This intermediary approach resolves the contradiction between enhancing Apxl production through calcium addition and ensuring reliable downstream processing.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If calcium salt is added to the culturing medium to enhance Apxl production, then transcriptional activity of the Apxl operon is enhanced, but precipitation of calcium salts occurs rendering calcium ions unavailable and causing filter clogging

Engineering Contradiction:

ImproveApxl production yieldVSAvoidease of downstream processing

Core Design Contradiction:

ProductivityVSEase of operation

Solution Approach 1:

Complexing agents serve as mediators between calcium ions and the bacterial cells. These agents maintain calcium ions in a soluble, bioavailable form throughout the fermentation process, preventing precipitation that would otherwise clog filters and complicate downstream processing. The complexing agent allows calcium to remain in solution while still being accessible for its transcriptional role, thus maintaining ease of operation.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent modifies the chemical environment of the culturing medium by introducing complexing agents that alter the availability and solubility parameters of calcium salts. By changing the chemical form of calcium from precipitated salts to soluble complexes, the patent maintains calcium's biological function while eliminating physical precipitation, thereby improving ease of downstream processing and filter performance.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If complexing agents are added to prevent calcium salt precipitation, then calcium ions remain available in solution, but Apxl production yield is negatively influenced

Engineering Contradiction:

Improvecalcium ion availabilityVSAvoidApxl production yield

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent carefully optimizes the concentration and type of complexing agent to achieve the right balance. By controlling parameters such as complexing agent concentration, pH, and calcium concentration ratios, the patent ensures that calcium remains sufficiently available for transcriptional activity while preventing precipitation. This parameter optimization resolves the contradiction between maintaining calcium availability and maximizing Apxl production yield.

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 approach significantly enhances Apxl production yields, reduces downstream processing issues, and achieves higher production levels even in animal component-free media, with optimal borogluconate concentrations between 25-45 mmol/l and increased carbon dioxide levels.

Implementation Method 1

which contains borogluconate to form a calcium borogluconate complex in the medium

Methodology Applied

Scientific EffectComplex formation: Chemical Bonding

Implementation Method 2

APP namely produces carbon dioxide which in the medium results in carbonate ions

Methodology Applied

Scientific EffectCarbon dioxide dissolution: Absorption (physical)

Implementation Method 3

transcriptional activity of the Apxl operon is enhanced by addition of calcium to the growth medium

Methodology Applied

Scientific EffectIon uptake: Absorption (physical)

Data Source

PatentEP2370590B1Process for producing the actinobacillus pleuropneumoniae toxin apxi employing a culture medium comprising calcium borogluconate

Publication Date: 2014.03.12 INTERVET INT BV

AI summary

The present invention pertains to a method to produce RTX-toxin Apxl by culturing Actinobacillus pleuropneumoniae bacteria in a liquid culturing medium that supports growth of the bacteria, to which medium a calcium salt is added to form calcium ions in the medium, wherein the culturing medium contains borogluconate to form a calcium borogluconate complex in the medium.