Phosphate-Free Detergent Protease Variant for Soft Water Cleaning
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Solution Overview
Problem
Existing automatic dishwashing detergents face challenges in maintaining effective cleaning performance, especially in soft water and under stressed conditions such as hot, long cycles, due to the negative impact of complexing agents on proteases.
Innovation Solution
A phosphate-free automatic dishwashing cleaning composition that incorporates a complexing agent system and a novel protease variant, which provides improved cleaning performance on proteinaceous stains like egg and crème brulee, even in soft water and under stressed conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If phosphate-free complexing agents are used to replace phosphates, then environmental performance is improved, but cleaning performance deteriorates due to negative impact on protease activity
Solution Approach 1:
The patent applies parameter changes by modifying the protease enzyme through site-directed mutagenesis to create variants with improved stability and activity. Specific amino acid substitutions (e.g., D127E, D127N, D127Q, D127R, D127S) are introduced to enhance the protease's resistance to complexing agents while maintaining phosphate-free formulation, thus resolving the contradiction between environmental performance and cleaning efficacy
Solution Approach 2:
The invention creates a composite enzyme system by combining the engineered protease variant with specific complexing agents (MGDA, IDS, GLDA, HBED) in a formulated detergent composition. This composite approach allows the protease to function effectively alongside phosphate-free complexing agents, achieving both environmental benefits and reliable cleaning performance on proteinaceous stains
2Ease of operation
If high levels of complexing agents are used in soft water conditions, then water softening performance is improved, but protease activity deteriorates due to extraction of structural calcium ions
Solution Approach 1:
The patent modifies the protease's structural parameters through amino acid substitution at position 127 (aspartic acid to glutamic acid, asparagine, glutamine, arginine, or serine). This parameter change strengthens the enzyme's calcium ion binding or structural stability, preventing calcium extraction by complexing agents in soft water conditions while maintaining high protease activity
Solution Approach 2:
The engineered protease acts as an intermediary between the complexing agents and calcium ions. The modified enzyme structure (particularly at position 127) creates a more stable calcium-binding site or protective structure that prevents complexing agents from extracting structural calcium, thus mediating the interaction to maintain both water softening and enzyme activity
3Reliability
If hot, long dishwashing cycles are used to clean toughest items, then cleaning performance is improved, but enzyme stability deteriorates due to thermal stress
Solution Approach 1:
The patent applies parameter changes by introducing multiple amino acid substitutions including D127E/N/Q/R/S and other positions (e.g., A37T, S39E, I43V, A47V, T56Y, I80V, N85S, E87D, S99R, T114Q, S126A, F128G, N242D). These cumulative parameter changes confer enhanced thermal stability to the protease, allowing it to maintain activity and structural integrity during hot, long dishwashing cycles while effectively cleaning toughest proteinaceous stains
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 delivers enhanced cleaning efficacy on tough stains, maintaining performance across various water hardness levels and cycle conditions, while being environmentally friendly by avoiding phosphates.
Implementation Method 1
a phosphate-free automatic dishwashing cleaning composition which comprises a complexing agent system and a novel protease... improved cleaning performance on egg and sugary stains such as crème brulee
Implementation Method 2
complexing agents can have a strong binding capacity for metals... the composition performs really well even when soft water is used... maintaining performance across various water hardness levels
Data Source
AI summary
A phosphate-free automatic dishwashing cleaning composition comprising: i) a protease wherein the protease is a variant having at least 60% identity with the amino acid sequence of SEQ ID NO:1 and comprising at least one amino acid substitution (using the SEQ ID NO: 1 numbering) selected from the group consisting of: X54T; X126A, D, G, V, E, K, I; X127E, S, T, A, P, G, C; and X128E, C, T, D, P, G, L, Y, N; and ii) from 10 to 50% by weight of the composition of a complexing agent system comprising from 0 to less than 30% by weight of the composition of citric acid.