Attenuated proP Gene for L-Methionine Fermentation
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Solution Overview
Problem
Current methods for producing L-methionine, a crucial amino acid, face challenges in achieving efficient overproduction due to metabolic control in wild-type microorganisms, requiring the development of strains with enhanced production capabilities.
Innovation Solution
Attenuating the proP gene in microorganisms of the Enterobacteriaceae family to reduce the activity of the ProP transporter, allowing for increased secretion and accumulation of L-methionine in the fermentation medium, thereby enhancing production efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If wild-type microorganisms are used for L-methionine production, then metabolic control maintains amino acid levels for cell needs, but production output remains limited and cannot achieve overproduction
Solution Approach 1:
The patent removes the metabolic control mechanism by deleting or inactivating the metJ repressor gene in E. coli or the metR repressor gene in S. marcescens. This extraction of the regulatory element allows the biosynthetic pathway to operate without feedback inhibition, enabling L-methionine overproduction beyond cellular needs while maintaining pathway functionality through constitutive expression promoters.
2Productivity
If conventional fermentation processes are used, then standard production levels are maintained, but achieving high overproduction requires complex strain development and process optimization
Solution Approach 1:
The patent employs constitutive expression promoters that continuously drive the biosynthetic pathway without regulatory interruptions. By replacing inducible or repressible promoters with constitutive ones (such as strong housekeeping gene promoters), the system maintains continuous L-methionine production throughout the fermentation process, eliminating the need for complex induction strategies or periodic process adjustments.
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 attenuation of the proP gene leads to increased production and secretion of L-methionine, enabling microorganisms to grow in higher methionine concentrations, thus improving the efficiency and yield of L-methionine production.
Implementation Method 1
process for the fermentative production of L-amino acids using microorganisms of the Enterobacteriaceae family
Data Source
AI summary
The present invention relates to a process for the fermentative production of L-amino acids using microorganisms of the Enterobacteriaceae family, which harbor an attenuated proP gene, to the microorganisms suitable for said production and to polynucleotides coding for variants of the ProP transporter.