Mutant Acetyl-CoA Hydrolase for Higher L-Glutamic Acid Fermentation
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Solution Overview
Problem
Existing methods for enhancing L-glutamic acid production in bacteria do not effectively utilize specific mutations in the acetyl-CoA hydrolase enzyme to improve production efficiency.
Innovation Solution
Modifying coryneform bacteria to harbor a mutant acetyl-CoA hydrolase with a specific amino acid substitution at position 383, such as lysine, cysteine, or other residues, to enhance L-glutamic acid production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the activity of acetyl-CoA hydrolase is reduced to enhance L-glutamic acid production, then L-glutamic acid production is improved, but the specific mechanism through amino acid sequence mutation has not been established
Solution Approach 1:
The patent applies parameter changes by modifying the amino acid sequence of acetyl-CoA hydrolase at position 383, substituting serine with other amino acids (such as lysine, glutamic acid, threonine, aspartic acid, asparagine, glutamine, arginine, cysteine, histidine, or methionine) to reduce enzyme activity and enhance L-glutamic acid production. This specific parameter modification resolves the contradiction by providing the missing mechanistic information while improving productivity
Solution Approach 2:
The patent applies local quality by making a specific localized change at position 383 in the acetyl-CoA hydrolase amino acid sequence. Instead of globally reducing enzyme activity through general methods, the invention targets a specific local region (amino acid position 383) to achieve the desired reduction in enzyme activity and improvement in L-glutamic acid production
2Productivity
If conventional methods are used to reduce acetyl-CoA hydrolase activity, then L-glutamic acid production is enhanced, but the efficiency and specificity are insufficient
Solution Approach 1:
The patent improves manufacturing precision by changing the specific parameter of amino acid identity at position 383 in the acetyl-CoA hydrolase sequence. This precise parameter modification enables controlled reduction of enzyme activity with high specificity, thereby improving both L-glutamic acid production and production efficiency simultaneously
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 modification significantly improves L-glutamic acid production capacity, allowing for accumulation of 0.5 g/L or more of the acid in the culture medium.
Implementation Method 1
Acetyl-CoA hydrolase is an enzyme that catalyzes the hydrolysis of acetyl-CoA to produce coenzyme A and acetic acid
Implementation Method 2
L-amino acids are industrially produced, for example, by a fermentation method using microorganisms such as bacteria capable of producing L-amino acids
Data Source
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AI summary
To provide a method for producing L-glutamic acid and a bacterium for use in the method. L-glutamic acid is produced by culturing a coryneform bacterium having the ability to produce L-glutamic acid and modified to harbor a mutant acetyl CoA hydrolase gene encoding a mutant acetyl CoA hydrolase having the substitution of a serine residue at position 383 in the amino acid sequence of wild-type acetyl CoA hydrolase substituted with another amino acid residue in a culture medium, and collecting L-glutamic acid from the culture medium and/or cells of the bacterium.