Streptococcus Fermentation and Purification via Fed-Batch and Adherent Filters
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Solution Overview
Problem
Current methods for producing bacterial capsular polysaccharides face challenges in achieving high yields and purity due to the complexity of continuous culture systems and the inefficiencies of existing purification processes, particularly the cationic detergent treatment which results in polysaccharide loss and is dependent on initial purity.
Innovation Solution
A simplified fed batch fermentation process for Streptococcus species, including two instantaneous yeast extract additions followed by a linear glucose addition, and the use of adherent filters for purification, which eliminates the need for cationic detergent treatment and reduces polysaccharide loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If continuous culture is used for capsular polysaccharide production, then productivity is improved, but device complexity and reliability deteriorate due to strain stability problems and contamination
Solution Approach 1:
The continuous culture process is segmented into multiple photobioreactor stages (open system and closed system stages) with distinct functions. The open system stage allows for acclimatization and initial growth, while the closed system stage maintains sterile conditions for high-density cultivation. This segmentation enables the system to achieve continuous culture productivity while mitigating contamination risks and strain stability issues through controlled transitions between stages.
2Productivity
If complex fed batch fermentation process is used, then productivity is improved, but device complexity and ease of operation worsen due to software complexity and algorithm requirements
Solution Approach 1:
The patent employs parameter changes to optimize fermentation conditions at different stages. Specifically, pH is adjusted from 7.0 in the initial phase to 6.5 during fed-batch cultivation, and dissolved oxygen tension is controlled at 30% saturation. These parameter modifications enhance polysaccharide yield while using standard, easily operable equipment without complex software algorithms, thereby improving both productivity and ease of operation.
3Manufacturing precision
If cationic detergent treatment is used in purification, then purity is improved, but loss of substance increases due to polysaccharide precipitation and loss
Solution Approach 1:
The patent replaces the cationic detergent treatment step with a recovery-oriented purification approach using ultrafiltration and dialysis. This method retains capsular polysaccharides in the retentate during ultrafiltration and recovers them through dialysis against buffered saline, achieving high purity (≥95%) while minimizing polysaccharide loss. The approach discards the harmful detergent step and recovers the product through gentle separation techniques.
4Manufacturing precision
If cationic detergent treatment is used in purification, then purity is improved, but device complexity increases due to additional precipitation and re-solubilization steps
Solution Approach 1:
The patent extracts and removes the problematic cationic detergent treatment step from the purification process. Instead, it employs ultrafiltration to separate polysaccharides from contaminants based on molecular weight, followed by dialysis to exchange buffers and remove residual impurities. This extraction of the harmful step simplifies the overall purification scheme, reducing device complexity while maintaining high purity levels.
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 achieves high yields of capsular polysaccharides with improved purity and reduced process complexity, overcoming the stability and contamination issues of continuous culture and enhancing the efficiency of the purification process.
Implementation Method 1
Fermentation processes for cultivating Streptococci and purification processes for obtaining cps therefrom
Implementation Method 2
the use of adherent filters for purification, which eliminates the need for cationic detergent treatment
Data Source
AI summary
This invention is in the field of bacterial cultures and specifically relates to the optimization of culture conditions to improve the production of bacterial capsular polysaccharides from Streptococcus strains in fed batch culture and to novel purification methods suitable for production scale purification of bacterial capsular polysaccharides from Streptococcus strains resulting in higher levels of purity than previously obtained for production scale.