Corynebacterium PPDK Engineering for Higher L-Tryptophan Yield
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Solution Overview
Problem
Existing methods for producing L-tryptophan in Corynebacterium microorganisms face challenges such as high energy requirements and decreased phosphoenol pyruvate levels due to by-product formation, leading to reduced L-tryptophan production.
Innovation Solution
Introduction of pyruvate, phosphate dikinase derived from Komagataeibacter xylinus or a polynucleotide encoding the same into Corynebacterium microorganisms to enhance L-tryptophan production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pyruvate, phosphate dikinase is introduced to increase phosphoenol pyruvate supply, then L-tryptophan production is improved, but energy consumption increases due to the enzyme's ATP-dependent mechanism
Solution Approach 1:
The patent introduces pyruvate, phosphate dikinase (PPDK) from Komagataeibacter xylinus with optimized expression levels and activity parameters. By controlling the expression strength and enzyme activity parameters, the system achieves effective phosphoenol pyruvate regeneration while minimizing excessive ATP consumption. The balanced expression strategy optimizes the trade-off between productivity enhancement and energy cost.
2Productivity
If transketolase expression is enhanced to increase E4P supply, then aromatic amino acid biosynthesis is improved, but intracellular energy levels decrease due to ATP consumption
Solution Approach 1:
The patent optimizes transketolase expression parameters by controlling promoter strength, copy number, and induction conditions. This parameter optimization ensures sufficient E4P supply for aromatic amino acid biosynthesis while preventing excessive ATP consumption that would deplete intracellular energy levels. The balanced expression strategy resolves the contradiction between productivity and energy maintenance.
3Productivity
If by-products such as acetic acid are produced during L-tryptophan fermentation, then fermentation activity is maintained, but phosphoenol pyruvate levels decrease leading to reduced L-tryptophan production
Solution Approach 1:
The patent introduces pyruvate, phosphate dikinase as an intermediary enzyme that converts pyruvate (which accumulates when phosphoenol pyruvate is consumed for L-tryptophan synthesis) back into phosphoenol pyruvate. This intermediary reaction pathway replenishes the phosphoenol pyruvate pool that is depleted during fermentation, thereby maintaining both by-product formation and high L-tryptophan production without phosphoenol pyruvate limitation.
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 microorganisms exhibit increased L-tryptophan production yields, making them suitable for industrial-scale production.
Implementation Method 1
pyruvate, phosphate dikinase derived from Komagataeibacter xylinus or a polynucleotide encoding the same is introduced
Implementation Method 2
a method for producing L-tryptophan, including culturing the microorganism in a medium
Data Source
AI summary
The present disclosure relates to a microorganism of the genus Corynebacterium having an L-tryptophan-producing ability, into which pyruvate, phosphate dikinase derived from Komagataeibacter xylinus or a polynucleotide encoding the same is introduced; a method for producing L-tryptophan, comprising culturing the microorganism in a medium; a composition for producing L-tryptophan, comprising the microorganism, a culture product of the microorganism, a fermented product of the microorganism, or a combination of two or more thereof; and the use of the microorganism for the production of L-tryptophan.