Chymosin Stabilization Using PEG Polymers
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Solution Overview
Problem
Current methods for stabilizing and isolating milk clotting aspartic protease enzymes, such as chymosin, do not effectively enhance their stability and activity, particularly in liquid and dried granulated compositions.
Innovation Solution
The addition of polyethylene glycol (PEG) or similar substituted polyoxyethylene compounds, like Brij35, to chymosin significantly improves the physical stability and specific activity of the enzyme by providing conformational stability, reducing precipitation during storage, and increasing storage stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional stabilizing methods (formate, acetate, lactate, propionate, malate, fumarate, propanediol) are used in liquid compositions, then storage stability is improved, but enzyme activity and specific activity are not significantly enhanced
Solution Approach 1:
The patent applies parameter changes by introducing PEG at specific concentrations (0.01-10% w/v) and molecular weights (200-50,000 g/mol) to fundamentally alter the stabilization mechanism. This differs from conventional small-molecule stabilizers by using a polymer that provides conformational stability through different physical interactions, thereby simultaneously improving both storage stability and specific activity without the trade-off present in conventional methods
Solution Approach 2:
The patent creates a composite system by combining PEG with chymosin in a liquid composition. This composite approach allows the PEG polymer to interact with the enzyme structure and provide enhanced stabilization while maintaining or improving catalytic activity, resolving the contradiction between stability and productivity that plagues conventional single-component stabilizer systems
2Productivity
If PEG is used for liquid-liquid two phase system (4-5% wt/vol PEG8000 with 10% wt/vol sodium sulfate), then chymosin recovery is achieved, but enzyme stability and specific activity are not significantly improved
Solution Approach 1:
The patent extracts the stabilization function from the recovery process itself. Instead of relying on high-concentration PEG (4-5% wt/vol) for phase separation and hoping for stability as a byproduct, the invention separately introduces optimized PEG concentrations (0.01-10% w/v) specifically for stabilization purposes, decoupling the recovery and stability functions to optimize each independently
3Productivity
If high concentration PEG (6% w/v PEG4600) is used for protein isolation, then dynamic binding capacity increases, but milk-clotting enzyme stability is not explicitly improved
Solution Approach 1:
The patent applies local quality by introducing PEG specifically to the enzyme solution at controlled concentrations (0.01-10% w/v) to provide localized conformational stabilization. This differs from using high-concentration PEG (6% w/v) as a general chromatography additive, where the stabilization effect is not the primary function and may be insufficient or non-specific
4Device complexity
If no polymer stabilizer is added, then composition is simple, but precipitation occurs during storage and specific activity is reduced
Solution Approach 1:
The patent uses inexpensive PEG polymers (available at 0.01-10% w/v concentrations) that can be easily added to and removed from the composition. These polymers provide temporary but effective stabilization during storage, preventing precipitation and maintaining specific activity without requiring complex formulation or expensive stabilizing agents
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 use of PEG or Brij35 results in a two-fold increase in specific activity and improved long-term storage stability of milk clotting aspartic protease enzymes, maintaining enzyme activity and preventing precipitation, even under physical stress like shaking.
Implementation Method 1
The addition of polyethylene glycol (PEG) or similar substituted polyoxyethylene compounds, like Brij35, to chymosin significantly improves the physical stability and specific activity of the enzyme by providing conformational stability
Implementation Method 2
reducing precipitation during storage, and increasing storage stability
Data Source
AI summary
A liquid or dried granulated milk clotting aspartic protease enzyme composition and process for isolating a milk clotting aspartic protease enzyme of interest.