Alkaline Protease Variants for Liquid Detergent Stability
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Solution Overview
Problem
Alkaline proteases in liquid detergents face stability issues due to denaturation and self-digestion, particularly in the presence of surfactants, leading to reduced effectiveness and increased production costs when using enzyme-stabilizing agents.
Innovation Solution
Development of an alkaline protease variant with specific amino acid substitutions, such as at positions 83, 6, 15, 16, 65, 66, 82, 204, and 337, which enhances stability in liquid detergents containing anionic surfactants like LAS, maintaining high specific activity and oxidizer resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional proteases are used in liquid detergents, then the detergent can degrade protein-based dirt, but the protease rapidly denatures and undergoes self-digestion leading to loss of activity
Solution Approach 1:
The patent applies parameter changes by substituting specific amino acid residues in the protease sequence with alternative residues having different properties. This modifies the enzyme's physical and chemical parameters to enhance its stability against denaturation and self-digestion while maintaining catalytic activity in liquid detergent formulations.
Solution Approach 2:
The patent applies local quality by making targeted amino acid substitutions at specific positions within the protease sequence rather than modifying the entire enzyme. This localized modification approach allows the protease to maintain its overall structure and function while gaining enhanced resistance to denaturation and self-digestion at critical sites.
2Reliability
If enzyme-stabilizing agents are added to protect protease, then storage stability improves, but production cost increases
Solution Approach 1:
The patent applies self-service by engineering the protease itself to possess inherent stability properties through amino acid substitution. The modified protease autonomously resists denaturation and self-digestion without requiring external stabilizing agents, thereby eliminating additional production costs associated with adding such agents.
Solution Approach 2:
The patent applies taking out by removing the need for external enzyme-stabilizing agents. Instead of adding separate stabilizing compounds to the detergent formulation, the stability function is extracted and built into the protease molecule itself through genetic modification.
3Productivity
If anionic surfactants are used in liquid detergents, then detergency performance improves, but protease stability deteriorates due to surfactant-induced denaturation
Solution Approach 1:
The patent applies blessing in disguise by converting the harmful interaction between anionic surfactants and protease into a beneficial outcome. The amino acid substitutions enable the protease to withstand surfactant exposure, allowing the detergent to utilize the strong cleaning power of anionic surfactants while protecting the protease from denaturation.
Solution Approach 2:
The patent applies beforehand cushioning by pre-engineering the protease with enhanced stability properties before it encounters the harsh detergent environment. The amino acid substitutions act as a protective cushion against surfactant-induced denaturation, allowing the protease to maintain activity in the presence of anionic surfactants.
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 alkaline protease variant exhibits improved stability and activity in liquid detergents, outperforming parent proteases in terms of residual activity and resistance to denaturation, thereby enhancing detergency and reducing production costs.
Implementation Method 1
protease is incorporated into a laundry detergent for providing the detergent with the ability to degrade dirt mainly composed of protein
Implementation Method 2
substituting a threonine residue at position 6 with a valine residue, and substituting an asparagine residue at position 83 with a glutamic acid residue
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
An alkaline protease variant derived from an alkaline protease consisting of an amino acid sequence represented by SEQ ID NO: 2 or consisting of an amino acid sequence having an identity of 90% or more therewith, which variant has mutations wherein one or more amino acid residues at positions selected from (a) position 6, (b) position 15, (c) position 16, (d) position 65, (e) position 66, (f) position 82, (g) position 83, (h) position 204, (i) position 319, and (j) position 337 of the amino acid sequence represented by SEQ ID NO: 2, or at positions corresponding thereto are substituted with the following amino acid residues: (a) or a position corresponding thereto: Typ, Leu, Val, Ile, Met, Tyr, Gln, Lys, Thr, Phe, Arg, Ser, Cys, Ala, or His; (b) or a position corresponding thereto: Glu, Met, Asp, Val, Gln, Arg, Cys, Trp, Ala, or Phe; (c) or a position corresponding thereto: Met, Glu, Arg, Val, Lys, Phe, Tyr, Ile, His, Asp, or Cys; (d) or a position corresponding thereto: Trp; (e) or a position corresponding thereto: His, Trp, Ser, or Leu; (f) or a position corresponding thereto: Ala, Glu, Gln, Ser, Cys, Gly, His, Lys, Arg, Met, or Asn; (g) or a position corresponding thereto: Ala, Ser, or Cys; (h) or a position corresponding thereto: Glu, Asp, Cys, Val, Thr, Pro, His, Ile, Trp, Ser, Asn, Lys, or Arg; (i) or a position corresponding thereto: Trp, Val, Thr, Leu, Ile, Cys, Glu, Lys, Tyr, Arg, Phe, Gln, Met, Pro, Asp, Asn, His, or Ser; and (j) or a position corresponding thereto: Arg, Gly, Ser, Lys, Gln, Thr, His, Ala, Cys, or Val.