Bacterial Polysaccharide Purification by Acid Sizing and Diafiltration

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Solution Overview

Problem

Current methods for purifying bacterial polysaccharides for vaccines are multi-step, costly, inefficient, and result in low recovery and high impurity content, compromising the efficacy and immunogenicity of the final product.

Innovation Solution

A method involving acid treatment of a fermentation harvest to separate and depolymerize polysaccharides, followed by diafiltration, effectively removing impurities and sizing the polysaccharides to a desired molecular weight range without using hazardous chemicals or enzymes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If multi-step purification methods are used, then impurity removal is improved, but polysaccharide recovery decreases and process complexity increases

Engineering Contradiction:

Improveimpurity removalVSAvoidpolysaccharide recovery

Core Design Contradiction:

Manufacturing precisionVSLoss of substance

Solution Approach 1:

The patent combines multiple purification functions (proteins removal, nucleic acids removal, endotoxins removal, and polysaccharide sizing) into a single acid treatment step using trifluoroacetic acid (TFA). This merging of functions achieves high impurity removal efficiency while maintaining high polysaccharide recovery (>60%) and avoiding the losses associated with multi-step conventional methods

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The acid treatment step serves multiple purposes simultaneously: it removes proteins, nucleic acids, and endotoxins, while also sizing the polysaccharides to the desired molecular weight range. This multi-functional approach eliminates the need for separate purification steps and enhances overall process efficiency

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Manufacturing precision

If conventional purification methods are used, then impurity removal is improved, but process cost and time increase

Engineering Contradiction:

Improveimpurity removalVSAvoidprocess time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

Multiple purification operations are merged into a single acid treatment step, reducing the total process time from hours to minutes while maintaining high impurity removal efficiency. The simultaneous removal of proteins, nucleic acids, endotoxins, and sizing of polysaccharides in one step eliminates sequential processing delays

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent uses a simple acid treatment approach with TFA that can be easily removed by evaporation or dialysis, replacing complex and expensive chromatographic methods. This approach significantly reduces both process time and operational costs while achieving comparable or superior purification results

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Productivity

If hazardous chemicals and enzymes are used, then purification efficiency is improved, but safety and environmental concerns increase

Engineering Contradiction:

Improvepurification efficiencyVSAvoidsafety and environmental concerns

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces hazardous chemicals (phenol, chloroform, CTAB) and enzymes with a simple acid treatment using TFA. The acid can be easily removed by evaporation or dialysis, leaving no harmful residues. This approach maintains high purification efficiency while eliminating safety and environmental concerns associated with conventional reagents

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent converts the potentially harmful acid treatment into a beneficial process by using TFA, which can be completely removed by evaporation or dialysis. The acid treatment effectively removes impurities and sizes polysaccharides while the easy removal of TFA eliminates harmful residues, turning a potentially harmful process into a safe and efficient purification method

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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

Achieves high polysaccharide recovery (>60%) with low impurity content (≤3% protein, ≤2% nucleic acid, ≤2% CWPs) and low polydispersity, ensuring the polysaccharide-protein conjugate vaccine exhibits improved stability and immunogenicity.

Implementation Method 1

treating a fermentation harvest with an acid to separate the polysaccharide from impurities (protein, nucleic acid and cell debris

Methodology Applied

Scientific EffectAcid treatment:

Implementation Method 2

The cell-free supernatant is subjected to diafiltration and concentration followed by incubation/treatment with an acid

Methodology Applied

Scientific EffectDiafiltration:

Data Source

PatentUS12473379B2Method for obtaining purified bacterial polysaccharides

Publication Date: 2025.11.18 SERUM INST OF INDIA PTE LTD

AI summary

The present disclosure relates to a method for obtaining purified bacterial polysaccharides. The method comprises simultaneous removal of impurities as well as sizing of bacterial polysaccharides using an acid instead of conventional mechanical sizing methods. The method is simple, rapid and cost effective. The method results in high polysaccharide recovery and low impurity content. The purified polysaccharide obtained by the method of the present disclosure may be used for large scale production of polysaccharide-protein conjugate vaccines.