Acetohydroxy Acid Synthase Variant for Feedback-Resistant L-Valine Production
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Solution Overview
Problem
The challenge lies in efficiently producing L-valine on a large industrial scale through fermentation due to feedback inhibition by the final product, limiting the yield of this essential amino acid.
Innovation Solution
A novel acetohydroxy acid synthase variant is developed, where the 137th amino acid is substituted, specifically with phenylalanine, to release feedback inhibition, enhancing the microorganism's ability to produce L-valine, including the use of a microorganism like Corynebacterium glutamicum with a modified acetohydroxy acid synthase variant, and a method for producing L-valine using this microorganism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If feedback inhibition is utilized in the biosynthesis pathway, then the microorganism maintains regulatory control over L-valine production, but the yield of L-valine is limited due to inhibition of the major enzymes by the final product
Solution Approach 1:
The patent applies parameter changes by modifying the amino acid sequence of acetohydroxy acid synthase at specific positions (137, 138, and/or 140) to alter the enzyme's sensitivity to L-valine feedback inhibition. This genetic modification changes the biochemical parameters of the enzyme, allowing it to function effectively even in the presence of high L-valine concentrations, thereby resolving the contradiction between maintaining regulatory control and achieving high productivity
2Device complexity
If the same enzyme is used for biosynthesis of branched-chain amino acids, then the metabolic pathway is simplified, but it becomes difficult to prepare a single kind of branched amino acid on a large industrial scale
Solution Approach 1:
The patent applies local quality by introducing site-specific mutations at particular amino acid positions (137, 138, and/or 140) of the acetohydroxy acid synthase enzyme. These localized changes modify the enzyme's substrate specificity and feedback inhibition characteristics, enabling it to preferentially catalyze L-valine production while maintaining the overall simplicity of the branched-chain amino acid biosynthesis pathway
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 microorganism shows a significant increase in L-valine production, with a 20.3% increase in yield compared to the parent strain, and further enhancements lead to improved productivity, overcoming the limitations of feedback inhibition.
Implementation Method 1
the biosynthesis also has a problem in that a feedback inhibition occurs on the major enzymes by the final product (i.e., L-valine) or a derivative thereof
Implementation Method 2
acetohydroxy acid synthase catalyzes decarboyxlation of pyruvate and a condensation reaction with another pyruvate molecule to produce acetolactate
Implementation Method 3
it is known that it is difficult to prepare a single kind of branched amino acid on a large industrial scale via fermentation
Data Source
AI summary
The present disclosure relates to an acetohydroxy acid synthase variant in which the feedback inhibition to L-valine is released, a polynucleotide encoding the acetohydroxy acid synthase variant, an expression vector including the polynucleotide, a microorganism producing L-valine including the acetohydroxy acid synthase variant, and a method for producing L-valine using the microorganism.