Phytase Enzyme Thermal Stability via Amino Acid Substitutions
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Solution Overview
Problem
Current phytase enzymes lack sufficient thermostability to withstand the high temperatures involved in animal feed pelleting, which limits their effectiveness in improving phosphorus and mineral bioavailability in animal feeds.
Innovation Solution
Development of variant phytase enzymes with enhanced thermal stability through specific amino acid substitutions, such as K46E, K65E, K97M, G103S, D112N, D144N, S209G, V227A, and G344D, which maintain or improve catalytic efficiency and stability at elevated temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wild-type phytase is used in animal feed, then it can hydrolyze phytate and improve mineral bioavailability, but it lacks sufficient thermostability to withstand high temperature feed-pelleting process
Solution Approach 1:
The patent applies parameter changes by systematically mutating specific amino acid residues (K46E, K65E, K97M, G103S, D112N, D144N, S209G, V227A, G344D) to alter the thermal stability parameters of the phytase enzyme. These point mutations change the local and global structural parameters of the protein, enabling it to maintain stability at higher temperatures during feed pelleting while preserving catalytic function.
Solution Approach 2:
The patent employs local quality by introducing specific amino acid substitutions at targeted positions within the phytase structure. Each mutation (e.g., K46E, K65E) modifies local structural properties such as hydrogen bonding, ionic interactions, or hydrophobic packing in specific regions, thereby enhancing overall thermostability without compromising the global catalytic mechanism.
2Reliability
If amino acid substitutions are introduced to improve thermostability, then thermal stability increases, but catalytic efficiency may be compromised
Solution Approach 1:
The patent carefully selects amino acid substitutions that change structural stability parameters without significantly altering catalytic parameters. The mutations are chosen to enhance thermal stability through improved packing, hydrogen bonding, or ionic interactions while maintaining the geometry and chemical environment of the active site, thus preserving catalytic efficiency.
Solution Approach 2:
The patent applies local quality by restricting mutations to specific positions away from the catalytic core or at positions where substitutions are likely to affect stability rather than activity. This ensures that local structural changes improve thermostability while the global catalytic function remains intact.
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 phytase enzymes demonstrate increased residual activity and melting temperatures, allowing their use in higher temperature feed preparation processes while maintaining or enhancing their ability to hydrolyze phytate and improve mineral bioavailability in animal feeds.
Implementation Method 1
Phytases (myo-inositol hexakisphosphate phosphohydrolase) catalyze the hydrolysis of phytate into myo-inositol and inorganic phosphate
Implementation Method 2
Development of variant phytase enzymes with enhanced thermal stability through specific amino acid substitutions, such as K46E, K65E, K97M, G103S, D112N, D144N, S209G, V227A, and G344D, which maintain or improve catalytic efficiency and stability at elevated temperatures
Data Source
AI summary
The invention provides variant phytase enzymes having increased thermal stability relative to their counterpart parent enzymes. The modifications to the enzymes include both single substitutions and various combinations of substitutions that provide improved stability and activity. The invention further provides nucleic acids encoding the variant phytase enzymes, host cells and vectors containing and expressing them, as well as feed compositions useful for providing improved nutrition, particularly with respect to the bioavailability of dietary phosphate, calcium, iron and zinc, among others.