Hexuronate C4-epimerase variant for stable D-tagatose production
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for producing tagatose are limited by the instability of lactose prices due to fluctuations in raw milk supply and demand, and existing enzyme variants for converting fructose to tagatose have suboptimal conversion activity, necessitating the development of a more efficient hexuronate C4-epimerase variant.
Innovation Solution
A hexuronate C4-epimerase variant with specific amino acid residue mutations, such as substituting tyrosine (Y)-403 with phenylalanine (F), serine (S)-125 with aspartic acid (D), and other targeted substitutions, is used to enhance the conversion activity from fructose to tagatose, allowing for efficient production using common sugars like fructose.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional methods using lactose as raw material are used for tagatose production, then tagatose can be produced through galactose isomerization, but the production cost becomes unstable due to fluctuations in raw milk supply and demand
Solution Approach 1:
The invention changes the raw material parameter from lactose/galactose to fructose, and modifies the enzyme parameter by creating hexuronate C4-epimerase variants with specific amino acid substitutions (S125D, V163A, D186N, F263I, D311G) to achieve stable and efficient tagatose production from the more versatile fructose原料
Solution Approach 2:
The invention enables the enzyme to catalyze the conversion of fructose to tagatose through C4-epimerization, providing a universal production route that can use common sugars (sugar, glucose, fructose) as raw materials, thereby increasing raw material flexibility and reducing dependency on lactose price fluctuations
2Productivity
If wild-type hexuronate C4-epimerase is used for fructose conversion, then the enzyme can catalyze the reaction, but the conversion activity to tagatose is insufficient for industrial production
Solution Approach 1:
The invention applies local quality modification by introducing specific amino acid substitutions at key positions (S125D, V163A, D186N, F263I, D311G) in the hexuronate C4-epimerase structure to enhance catalytic activity at the active site, thereby improving overall conversion efficiency without requiring complete structural redesign
Solution Approach 2:
The invention changes the enzyme's kinetic parameters through site-directed mutagenesis, creating variants with improved kcat/Km ratios for fructose conversion, thereby achieving higher productivity while maintaining the basic enzyme structure
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 mutated hexuronate C4-epimerase variant significantly increases the conversion activity of fructose to tagatose, enabling cost-effective mass production of tagatose using universal raw materials like fructose, thereby stabilizing the production process and reducing costs.
Implementation Method 1
a hexuronate C4-epimerase variant having improved activity of converting D-fructose into D-tagatose by epimerizing D-fructose at carbon number 4
Data Source
AI summary
Provided are a hexuronate C4-epimerase variant with improved activity in converting D-fructose by D-tagatose of hexuronate C4-epimerase and a method for production of D-tagatose using them.