Mutant GlyA Bacteria for Higher L-Glutamic Acid Yield
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Solution Overview
Problem
Existing methods for producing L-glutamic acid using bacteria are inefficient and require improvements to enhance production capabilities.
Innovation Solution
Modifying coryneform bacteria with specific genetic mutations in the serine hydroxymethyltransferase enzyme, such as substituting the glycine residue at position 265 with another amino acid, to improve L-glutamic acid production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If wild-type serine hydroxymethyltransferase is used in coryneform bacteria, then the bacteria can maintain normal metabolic function, but L-glutamic acid production ability is insufficient
Solution Approach 1:
The invention applies parameter changes by substituting specific amino acid residues (Gly265, Gly268, Gly271) in the serine hydroxymethyltransferase enzyme with other amino acids. This modifies the enzyme's catalytic properties and substrate binding characteristics, thereby enhancing L-glutamic acid production while maintaining sufficient metabolic function through controlled genetic modification rather than complete enzyme replacement
2Productivity
If serine hydroxymethyltransferase activity is increased to improve L-glutamic acid production, then productivity increases, but the complexity of metabolic pathway control increases
Solution Approach 1:
The invention applies local quality by making specific, targeted modifications only at three critical amino acid positions (265, 268, 271) in the serine hydroxymethyltransferase enzyme rather than attempting to control the entire metabolic pathway. This localized approach enhances L-glutamic acid production through specific enzymatic property changes while avoiding the complexity of comprehensive metabolic pathway engineering
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
Enhances the bacteria's ability to produce L-glutamic acid, allowing for higher yields in the culture medium and bacterial cells.
Implementation Method 1
Serine hydroxymethyltransferase is an enzyme having the activity to catalyze the hydroxymethyltransfer reaction of serine and/or glycine
Implementation Method 2
a method for producing L-glutamic acid, comprising culturing the coryneform bacterium described in any of 1 to 8 in a culture medium to accumulate L-glutamic acid in the culture medium and/or in cells of the bacterium
Data Source
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AI summary
Provided are a method for producing L-glutamic acid and a bacterium for use in said method. A coryneform bacterium modified to harbor a mutant glyA gene encoding a mutant serine hydroxymethyltransferase having the substitution of a glycine residue at position 265 in the amino acid sequence of wild-type serine hydroxymethyltransferase with another amino acid residue is cultured in a culture medium, and L-glutamic acid is collected from the culture medium and/or cells of the bacterium, thereby L-glutamic acid is produced.