Mutant C. Glutamicum Strain for High-Viscosity Hyaluronic Acid Fermentation
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Solution Overview
Problem
The viscosity of the fermentation broth during Corynebacterium glutamicum production of hyaluronic acid and other mucopolysaccharides inhibits metabolic activities due to reduced oxygen levels, limiting yield.
Innovation Solution
A Corynebacterium glutamicum strain engineered with specific mutations at sites 862902, 862903, 862953, 862961, 862958, and 862963, along with overexpression of hyaluronic acid synthase and key enzymes, enhances tolerance to high-viscosity environments and improves metabolic efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If Corynebacterium glutamicum is used to produce hyaluronic acid and other viscous substances, then the yield of mucopolysaccharides increases, but the fermentation broth becomes viscous, reducing dissolved oxygen and inhibiting metabolic activities
Solution Approach 1:
The patent applies parameter changes by mutating specific genes (pyrF, purS, purL, purM) to alter the physiological parameters of Corynebacterium glutamicum, enabling it to tolerate high-viscosity environments. The mutations modify enzyme activities in pyrimidine and purine metabolism pathways, changing cellular responses to viscosity stress and allowing continued metabolic activity even when broth viscosity reduces dissolved oxygen availability.
2Productivity
If the fermentation broth becomes viscous due to mucopolysaccharide accumulation, then the production of hyaluronic acid increases, but dissolved oxygen levels decrease, affecting normal metabolic activities
Solution Approach 1:
The patent implements feedback mechanisms where the mutated genes create a regulatory system that responds to viscosity-induced stress. The modified purine and pyrimidine metabolism pathways provide feedback loops that adjust cellular metabolism in response to dissolved oxygen levels and viscosity conditions, maintaining metabolic activity stability throughout the fermentation process even as hyaluronic acid accumulates and broth viscosity increases.
Data Source
AI summary
The Corynebacterium glutamicum strain of the present invention is obtained by mutating Corynebacterium glutamicum ATCC 13032, with the mutation sites including: mutating cytosine at site 862902 into thymine; mutating guanine at site 862903 into adenine; mutating cytosine at site 862953 into thymine; mutating adenine at site 862961 into guanine; inserting cytosine and thymine at site 862958; and mutating of guanine at site 862963 by deletion. The Corynebacterium glutamicum strain of the present invention exhibits significantly increased tolerance in high-viscosity environments and growth and metabolism ability under low dissolved oxygen conditions, thereby increasing the yield of mucopolysaccharides, and avoiding the problems where resulting mucopolysaccharides cause the fermentation broth to become viscous and have insufficient dissolved oxygen, which would further limit the metabolism of Corynebacterium glutamicum and ultimately affect the synthesis of mucopolysaccharides.