Targeted Phytase Mutations for Heat-Resistant Feed Pelleting
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Solution Overview
Problem
Existing phytase enzymes, particularly those derived from Escherichia coli (APPA), exhibit poor thermal stability during the pelleting process of animal feed, leading to reduced enzyme activity and increased costs due to the need for additional equipment and stability measures.
Innovation Solution
Development of a phytase mutant with improved heat resistance through targeted amino acid substitutions, specifically at positions 36, 69, 89, 91, 202, 213, 225, 238, 243, 253, and 266, enhancing the enzyme's stability under high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If bacterial phytase APPA is directly added to powder feed or spray coated on pellet feed, then phosphorus utilization is improved, but thermal stability during pelleting process deteriorates
Solution Approach 1:
The patent applies parameter changes by modifying the amino acid sequence of the phytase enzyme through site-directed mutagenesis. Specific amino acid residues (such as Phe84, Phe170, Phe284, Trp302) are mutated to alter the enzyme's thermal stability parameters while preserving its catalytic activity. This allows the enzyme to withstand the high temperatures (80-90°C) of the pelleting process, resolving the contradiction between maintaining phosphorus utilization effectiveness and improving thermal stability.
2Reliability
If spray coating method is used to apply phytase on pellet feed, then enzyme stability is improved, but equipment cost and process complexity increase
Solution Approach 1:
The patent applies preliminary action by pre-modifying the phytase enzyme's thermal stability characteristics through genetic mutation before it is applied to the feed. This preliminary engineering of the enzyme itself eliminates the need for subsequent protective measures such as spray coating equipment, special storage facilities, or complex application systems. The enzyme inherently resists thermal degradation, allowing for simple mixing and feeding processes without additional equipment investment.
Data Source
AI summary
The present invention relates to the technical field of biology, in particular to a phytase mutant, a preparation method therefor and an application thereof, a DNA molecule encoding the phytase mutant, a vector, and a host cell. The mutant provided by the present invention contains the substituent of an amino acid at at least one position selected from the following group: 36, 69, 89, 91, 111, 202, 213, 225, 238, 243, 253, 258, and 266. The heat resistance of the mutant is significantly improved, thereby facilitating the wide application of the phytase in feed.