Protease Variant Stability in Phosphate-Free Dishwashing
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Solution Overview
Problem
Conventional automatic dishwashing compositions face challenges in maintaining cleaning performance across varying water hardness and conditions, particularly in soft water and under stressed conditions like hot, long cycles, due to the negative effects of high levels of bleaching agents and complexing agents on proteases.
Innovation Solution
A phosphate-free automatic dishwashing composition incorporating a specific variant protease with high sequence identity, a complexing agent system, and a high-level bleaching system, optimized for use in soft water and hot, long cycles, which enhances proteinaceous cleaning efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high levels of bleaching agents are used to provide good cleaning, then cleaning performance is improved, but protease stability and activity deteriorate
Solution Approach 1:
The patent applies parameter changes by modifying the protease enzyme through site-directed mutagenesis to create variants with enhanced stability. Specific amino acid substitutions (e.g., Phe177→Met, Ser182→Ala) are introduced to alter the enzyme's physical and chemical properties, making it more resistant to oxidation by bleaching agents while maintaining proteolytic activity. This resolves the contradiction by changing the protease's parameters rather than reducing bleach levels.
Solution Approach 2:
The patent converts the harmful oxidative effect of bleaching agents into a beneficial selection pressure. The mutated protease variants are specifically designed to withstand oxidative stress from high-level bleach, transforming the previously damaging environment into one where the engineered protease thrives. The bleach that would normally destroy conventional proteases now serves to highlight and select for the superior stability of the mutated variants.
2Object-affected harmful factors
If high levels of complexing agents are used to replace phosphates, then environmental profile is improved, but protease activity deteriorates due to extraction of structural calcium
Solution Approach 1:
The patent applies parameter changes by modifying the protease's metal ion binding characteristics through amino acid mutations. The mutated protease variants have altered affinity and specificity for calcium ions, maintaining structural integrity even in the presence of high levels of complexing agents like citric acid or gluconate that would otherwise strip calcium from conventional proteases. This allows the use of environmentally friendly complexing agents without sacrificing protease activity.
3Productivity
If composition is optimized for soft water performance, then cleaning in soft water is improved, but performance in hard water deteriorates
Solution Approach 1:
The patent applies universality by creating a protease variant that performs effectively across multiple water hardness conditions. The mutated protease maintains high activity and stability whether the water is soft or hard, eliminating the need to optimize separate formulations for different water types. This multi-functional protease works universally in various water conditions, resolving the contradiction between soft water optimization and hard water performance.
4Object-affected harmful factors
If conventional proteases are used in phosphate-free compositions with high bleach, then environmental profile is improved, but cleaning performance under stressed conditions deteriorates
Solution Approach 1:
The patent applies parameter changes by engineering protease variants with modified amino acid sequences that confer enhanced stability under stressed conditions. The mutations (e.g., Phe177→Met, Ser182→Ala) alter the protease's physical parameters such as thermal stability, oxidative resistance, and pH tolerance, enabling it to maintain high cleaning performance in environmentally friendly formulations containing high levels of bleach and operated under demanding conditions like hot, long cycles.
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 composition provides improved cleaning performance on tough soils like egg and crème brulee, maintaining effectiveness even in soft water and stressed conditions, while minimizing the adverse effects of bleaching and complexing agents on enzymes.
Implementation Method 1
a specific protease... provides improved cleaning even when soft water and/or high temperatures and/or long cycles are used
Implementation Method 2
comprising a complexing agent system... can have a strong binding capacity for metals
Implementation Method 3
a high level of a bleaching system... the bleach can also impair on the performance of enzymes
Data Source
AI summary
A phosphate-free automatic dishwashing cleaning composition comprising an organic complexing agent system and a new protease.