appA2C Phytase Variants for Thermostability and Catalytic Rate
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Solution Overview
Problem
Commercially available phytases exhibit limitations in thermostability and catalytic activity, leading to reduced effectiveness in releasing inorganic phosphate from phytate in animal feed, resulting in nutritional deficiencies and environmental phosphate pollution in livestock production.
Innovation Solution
Development of appA2C phytase variants with specific mutations at positions 4, 62, 137, 159, 185, 211, 255, and 327, which enhance thermostability and maintain broad pH optimum and fast enzyme kinetics, comparable to or exceeding that of existing phytases like OptiPhos and Quantum Blue 5G.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If commercially available phytases are used to release inorganic phosphate from phytate in animal feed, then catalytic activity is achieved, but thermostability is insufficient leading to reduced effectiveness after heat treatment
Solution Approach 1:
The patent applies parameter changes by introducing specific amino acid mutations at positions 4, 62, 137, 159, 185, 211, 255, and 327 in the phytase enzyme sequence. These mutations modify the enzyme's structural and functional parameters to achieve enhanced thermostability while maintaining catalytic activity, allowing the enzyme to retain effectiveness after heat treatment during feed pelleting.
Solution Approach 2:
The patent creates a composite enzyme variant by combining multiple specific mutations in the phytase protein structure. This composite approach integrates several amino acid changes that work synergistically to provide both thermostability and high catalytic activity, resolving the contradiction between stability and productivity.
2Productivity
If phytase activity is maintained during heat treatment for feed pelleting, then catalytic efficacy is improved, but enzyme stability at high temperatures is compromised
Solution Approach 1:
The patent modifies the enzyme's thermal and catalytic parameters through specific amino acid substitutions. The mutations at positions 4, 62, 137, 159, 185, 211, 255, and 327 adjust the enzyme's structural flexibility and active site characteristics, enabling it to maintain high catalytic efficacy while withstanding heat treatment temperatures without denaturation.
Solution Approach 2:
The patent enhances the dynamic properties of the enzyme by introducing mutations that optimize the balance between structural rigidity for stability and flexibility for catalytic activity. This allows the enzyme to adapt its conformation during heat treatment while maintaining functional performance.
3Productivity
If commercial phytases are used to improve mineral availability in monogastric animal feed, then phosphate release is achieved, but nutritional deficiencies and environmental pollution occur due to insufficient activity
Solution Approach 1:
The patent optimizes the enzyme's kinetic parameters through amino acid mutations, enhancing the phosphate release rate and ensuring reliable nutritional effectiveness. The mutations improve the enzyme's performance in the specific physiological conditions of monogastric animals, ensuring adequate phosphate availability without causing environmental pollution.
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 appA2C variants demonstrate significantly improved thermostability, retaining 50% activity at higher temperatures, enhancing the nutritional value of animal feed and reducing phosphate pollution by maintaining enzyme activity during heat treatment processes.
Implementation Method 1
Phytases are capable of catalyzing hydrolysis of myo-inositol hexaphosphate to D-myo-inositol pentaphosphate and orthophosphate
Implementation Method 2
When the phosphate groups of phytic acid are removed by the seed enzyme phytase, the ability to bind metal ions is lost and the minerals become available to the plant
Data Source
AI summary
The present invention provides phytase enzymes exhibiting a surprisingly high thermostability as compared to commercially available phytases. Additionally some of the new phytase variants display up to four fold increased catalytic rate thus greatly increased speed of phytate dephosphorilation.