LysE-Inactivated Microorganisms for GAA Fermentation
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Solution Overview
Problem
Existing methods for producing guanidinoacetic acid (GAA) and creatine are limited by the export of L-arginine by the amino acid exporter LysE, which reduces substrate availability and inhibits high yields.
Innovation Solution
A genetically modified microorganism with decreased activity of the arginine exporter and increased expression of L-arginine:glycine amidinotransferase (AGAT) is developed, along with overexpression of enzymes in the arginine biosynthetic pathway, to enhance L-arginine production and facilitate GAA and creatine synthesis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the amino acid exporter LysE is active, then the microorganism can export amino acids for normal cellular function, but L-arginine is exported which reduces substrate availability and inhibits high yields of GAA and creatine
Solution Approach 1:
The harmful function of LysE in exporting L-arginine is removed by inactivating the lysE gene. This extraction of the problematic export function allows L-arginine to accumulate intracellularly as substrate for GAA and creatine production, resolving the contradiction between normal amino acid export function and high-yield product formation
Solution Approach 2:
The activity of the LysE exporter is changed from active to inactive state through gene inactivation. This parameter change prevents L-arginine export, increasing intracellular substrate availability for the desired biosynthetic pathway while eliminating the competing export function
2Productivity
If L-arginine biosynthesis is enhanced, then more substrate is available for GAA production, but the exported L-arginine is lost reducing overall efficiency
Solution Approach 1:
The harmful export action of LysE is preemptively blocked by inactivating the lysE gene before L-arginine can be exported. This preliminary anti-action ensures that enhanced L-arginine biosynthesis is fully utilized for GAA and creatine production without loss to export, resolving the contradiction between production rate and substance retention
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 effectively increases L-arginine production and subsequent GAA and creatine yields, overcoming the limitations of substrate export and enhancing fermentation efficiency.
Implementation Method 1
GAA and ornithine are formed from arginine and glycine as starting materials by the catalytic action of an L-arginine:glycine-amidinotransferase (AGAT; EC 2.1.4.1)
Implementation Method 2
The present invention pertains to a method to produce GAA by a fermentative process using industrial feed stocks (e.g. ammonia, ammonium salts and glucose or sugar containing substrates) as starting material
Data Source
AI summary
A microorganism is transformed to be capable of producing guanidinoacetic acid (GAA) having an inactivated amino acid exporter. The microorganism is used in a method for the fermentative production of GAA. Moreover, creatine is produced by a method of fermentative production.