Mutant Hexuronate C4-Epimerase for D-Fructose Conversion
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Solution Overview
Problem
The production of D-tagatose is hindered by the unstable price of lactose, a raw material, making it difficult to maintain a stable supply due to fluctuations in demand and supply on the global market, necessitating a new method using general saccharides like sucrose, glucose, and fructose.
Innovation Solution
A hexuronate C4-epimerase variant with specific amino acid mutations is developed to enhance conversion activity, allowing for the production of D-tagatose from D-fructose, utilizing a method that includes contacting D-fructose with the variant enzyme to epimerize it at the C4 position, thereby producing D-tagatose efficiently and economically.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If lactose is used as a raw material for tagatose production, then tagatose can be produced through enzymatic isomerization, but the price and supply stability of raw materials become unstable due to global market fluctuations
Solution Approach 1:
The invention changes the substrate parameter from lactose to D-fructose, allowing the enzyme to catalyze a different reaction pathway. The mutated hexuronate C4-epimerase can now accept D-fructose as a substrate and produce D-tagatose through C4-epimerization, thereby decoupling production from the unstable lactose market while maintaining production capability
Solution Approach 2:
The mutated enzyme gains multi-functionality by being able to process different saccharides (sucrose, glucose, fructose) as raw materials. This universality allows the production system to adapt to various readily available sugar sources, ensuring continuous production even when one raw material source becomes unavailable or expensive
2Productivity
If conventional hexuronate C4-epimerase is used for D-fructose conversion, then the enzyme can catalyze the reaction, but the conversion activity and unit activity are insufficient for efficient production
Solution Approach 1:
The invention modifies the enzyme's amino acid sequence parameters through site-directed mutagenesis at specific positions (S125, S185, V267, S268, T272, W306, R386, Y403). These parameter changes in the enzyme structure enhance its catalytic efficiency and unit activity, enabling efficient conversion of D-fructose to D-tagatose
Solution Approach 2:
The invention replaces the conventional enzyme with a genetically engineered variant that has optimized catalytic properties. The mutated enzyme provides superior conversion activity compared to the wild type, thereby improving manufacturing efficiency without requiring changes to the overall process architecture
3Reliability
If new methods using general saccharides are developed, then raw material supply stability improves, but new enzyme variants with improved activity must be created
Solution Approach 1:
The invention systematically modifies specific amino acid positions in the enzyme sequence to optimize its properties for processing general saccharides. By focusing mutations at predetermined key positions, the complexity of enzyme development is managed while achieving the desired improved activity and substrate versatility
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 hexuronate C4-epimerase variant effectively converts D-fructose to D-tagatose with improved unit activity, enabling high-yield production in a cost-effective manner, reducing manufacturing costs and overcoming raw material supply issues.
Implementation Method 1
contacting D-fructose with the hexuronate C4-epimerase variant to epimerize it at the C4 position, thereby producing D-tagatose
Data Source
AI summary
A hexuronate C4-epimerase with improved conversion activity and a method for producing D-tagatose using the hexuronate C4-epimerase. The hexuronate C4-epimerase includes an amino acid sequence set forth in SEQ ID NO: 1, in which serine (S) at position 125, serine (S) at position 185, valine (V) at position 267, serine (S) at position 268, threonine (T) at position 272, tryptophan (W) at position 306, arginine (R) at position 386 and tyrosine (Y) at position 403 from an N-terminal of hexunorate C4-epimerase are mutated.