Capsular Polysaccharide Purification Using Quaternary Ammonium Membranes
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Solution Overview
Problem
Existing methods for purifying capsular polysaccharides from bacterial cells are complex, expensive, and inefficient, particularly when dealing with high initial loads or aggregate forms, and often require toxic reagents and specialized facilities.
Innovation Solution
A method involving the use of a reinforced cellulose membrane with quaternary ammonium ligand followed by silicon dioxide (SiO2) treatment to purify capsular polysaccharides, optimizing pH ranges to bind negatively charged impurities effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple complex purification steps including chromatography, detergents, and solvents are used, then impurity removal is improved, but process complexity and cost increase
Solution Approach 1:
The patent combines multiple purification functions (chromatography, filtration, and adsorption) into a single integrated column system containing both cellulose and activated carbon layers. This merging eliminates the need for separate purification steps while maintaining high purification efficiency, directly resolving the contradiction between purification effectiveness and process complexity
Solution Approach 2:
The integrated column system performs multiple functions simultaneously: cellulose removes proteins and cellular debris through adsorption, while activated carbon removes nucleic acids and other impurities. This multi-functional approach replaces multiple specialized purification steps with a single versatile system, reducing process complexity without sacrificing purification quality
2Manufacturing precision
If toxic reagents like phenol, butanol, and chloroform are used for purification, then impurity removal is improved, but safety and environmental impact worsen
Solution Approach 1:
The patent replaces harmful chemical reagents with benign natural materials: cellulose (a natural polymer) and activated carbon (a safe adsorbent). These materials achieve equivalent or superior purification efficiency without the toxic side effects, converting a harmful purification approach into a safe one while maintaining effectiveness
Solution Approach 2:
The integrated column with cellulose and activated carbon can be used as a disposable or easily replaceable unit. Instead of using expensive and hazardous chemicals that require special handling and disposal, the system uses inexpensive, non-toxic materials that can be discarded after use, eliminating toxic waste management issues while maintaining high purification standards
3Manufacturing precision
If multiple precipitation and filtration steps are used, then nucleic acid removal is improved, but processing time increases
Solution Approach 1:
The patent merges the functions of multiple precipitation and filtration steps into a single column passage. The cellulose and activated carbon layers work together in one continuous process to remove proteins, nucleic acids, and cellular debris simultaneously, eliminating the need for sequential precipitation and filtration steps while achieving superior nucleic acid removal
Solution Approach 2:
The integrated column is pre-configured with cellulose and activated carbon in specific arrangements that optimize their complementary actions. Cellulose first captures proteins and larger debris, while activated carbon subsequently removes nucleic acids and smaller impurities. This pre-arranged sequence performs multiple purification functions in one pass, dramatically reducing processing time compared to sequential steps
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 achieves high-purity capsular polysaccharides meeting WHO specifications with reduced processing time and cost, without the need for toxic reagents or complex chromatography, suitable for commercial scale-up.
Implementation Method 1
passing the sized crude capsular polysaccharide solution through a reinforced cellulose membrane having quaternary ammonium as ligand
Implementation Method 2
contacting the solution obtained after passing through the reinforced cellulose membrane having quaternary ammonium, in step (d), with SiO2 and isolating the capsular polysaccharide in a pure form
Data Source
AI summary
The present invention broadly relates to the improved method for purification of capsular polysaccharides. Particularly, the present invention relates to the method of purification of capsular polysaccharides from Streptococcus pneumoniae and other similar related capsular polysaccharides produced from both gram-negative and gram-positive microorganisms. More particularly, the invention involves passing the crude capsular polysaccharide solution through reinforced cellulose membrane having quaternary ammonium, and further contacting the solution with silicon dioxide (SiO2) and isolating the capsular polysaccharide in a pure form. The purified capsular polysaccharide is useful for producing vaccines that contain the polysaccharide alone or are conjugated to proteins.