Subtilase Variant Stability in Liquid Detergents

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Solution Overview

Problem

Existing liquid detergents face a challenge with the decrease in enzyme activity over time, particularly with subtilases, leading to reduced stain removal performance due to instability under alkaline conditions.

Innovation Solution

A novel subtilase variant with increased stability is introduced, featuring specific amino acid substitutions (X9E+X206L+X262E), which maintains enzyme activity during storage and use, outperforming traditional subtilases like Relase™ and Savinase™ in retaining protease activity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional subtilases (e.g., Relase™, Savinase™) are used in liquid detergents, then initial protease activity is sufficient for stain removal, but enzyme activity decreases over time during storage and use, leading to reduced effectiveness

Engineering Contradiction:
Improveenzyme stabilityVSAvoidenzyme activity retention
Core Design Contradiction:
ReliabilityVSDuration of action of moving object

Solution Approach 1:

The patent applies parameter changes by modifying the amino acid sequence of subtilase at specific positions (9, 206, and 262) to create variant forms with improved stability. The substitutions include changing amino acids at these positions to specific alternatives that enhance the enzyme's resistance to degradation under alkaline storage conditions while maintaining its proteolytic activity for stain removal.

Inventive Principle:
Principle #35Parameter changes

2Duration of action of stationary object

If subtilase variants with improved stability are developed, then enzyme activity is maintained longer during storage, but this requires complex amino acid substitution modifications at multiple positions

Engineering Contradiction:
Improvestorage stabilityVSAvoidprotein structure modification
Core Design Contradiction:
Duration of action of stationary objectVSDevice complexity

Solution Approach 1:

The patent applies local quality by making targeted amino acid substitutions at specific local positions (9, 206, and 262) within the subtilase protein structure rather than attempting to modify the entire protein. This localized approach allows for improved stability through focused modifications at key residues that are critical for maintaining enzyme integrity under storage conditions.

Inventive Principle:
Principle #3Local quality

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 subtilase variant demonstrates enhanced stability, maintaining 80-100% residual activity after 4 weeks at 37°C and 45°C, comparable to 1.0% w/w Relase™, while maintaining parity in wash performance on various stains, thus extending the detergent's effectiveness.

Implementation Method 1

subtilasin-like serine proteases from bacilli... are of particular interest... ability to remove proteinaceous stains from fabric under alkaline conditions

Methodology Applied
Scientific EffectProteolysis: Hydrolysis

Data Source

PatentEP3380599B1A liquid detergent composition
Publication Date: 2019.03.06 UNILEVER NV
  • EP3380599B1 patent drawingFigure 1

AI summary

The present invention relates to a liquid detergent composition comprising a novel protease, more in particular a novel and subtilase variant with increased stability, a method for (dish) washing using said liquid detergent composition and a use of said liquid composition in a (dish) washing process.