PET Hydrolase Thermal Stability via N248P Mutation
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Solution Overview
Problem
Current PET biodegradation enzymes, such as IsPETase, have low degradation efficiency and thermal stability, limiting their industrial application in effectively degrading polyethylene terephthalate (PET) plastic waste.
Innovation Solution
Modification of the PET hydrolase enzyme through structural analysis and site-directed mutagenesis, specifically substituting asparagine at position 248 with proline, to enhance its thermal stability, as demonstrated by the mutation from LCC-ICCG to LCC-ICCG-N248P, which improves heat tolerance and PET degradation rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing PET hydrolases (e.g., IsPETase) are used for PET degradation, then PET biodegradation is achieved, but thermal stability and degradation efficiency remain low
Solution Approach 1:
The patent applies parameter changes by substituting asparagine at position 248 with proline in the PET hydrolase sequence. This amino acid substitution modifies the enzyme's thermal stability parameter, allowing it to maintain higher activity at elevated temperatures (70-90°C), thereby resolving the contradiction between thermal stability and degradation efficiency
Solution Approach 2:
The patent applies local quality by making a targeted local modification at position 248 of the enzyme sequence. Instead of globally altering the enzyme structure, a specific local substitution (N248P) is introduced to enhance thermal stability while preserving the overall catalytic function and degradation efficiency
2Productivity
If PET degradation is performed at higher temperatures to increase degradation rate, then productivity improves, but enzyme thermal stability becomes insufficient
Solution Approach 1:
The patent changes the temperature parameter at which the enzyme operates by improving its thermal stability through the N248P mutation. This allows the enzyme to function effectively at higher temperatures (70-90°C), simultaneously achieving both high degradation rates and maintaining enzyme stability at these elevated temperatures
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 modified PET hydrolase, LCC-ICCG-N248P, exhibits significantly higher PET-hydrolytic activity at elevated temperatures, increasing its industrial application value and potential for efficient PET degradation.
Implementation Method 1
PET is composed of ester bond-linked terephthalic acid (TPA) and ethylene glycol (EG)... The biodegradation technology (enzymatic degradation or microbial degradation) can degrade PET into small molecules... PET hydrolase... exhibits significantly higher PET-hydrolytic activity
Data Source
AI summary
A PET hydrolase having improved thermal stability is disclosed. The PET hydrolase has a modified amino acid sequence of SEQ ID NO: 2 or a modified amino acid sequence with at least 80% sequence identity of SEQ ID NO: 2, wherein the modification is a substitution of asparagine at position 248 or a corresponding position with proline.