Glucoamylase Variants for Starch Conversion
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Solution Overview
Problem
Current glucoamylases used in starch conversion processes have limitations in terms of thermo-stability and glucose tolerance, which affect the efficiency of fermentation product production, particularly in one-step ethanol fermentation from un-gelatinized starch.
Innovation Solution
Development of glucoamylase variants with specific substitutions at positions 95, 59, 119, 121, and 426, enhancing thermo-stability and glucose tolerance, allowing for improved activity and efficiency in starch conversion processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional glucoamylases are used in starch conversion processes, then the process can proceed with standard enzymes, but the thermo-stability and glucose tolerance are insufficient, limiting fermentation efficiency
Solution Approach 1:
The patent applies parameter changes by introducing specific amino acid substitutions at positions 95, 59, 119, 121, and 426 of the glucoamylase sequence. These substitutions modify the enzyme's physical and chemical properties to enhance thermo-stability and glucose tolerance, directly resolving the contradiction between reliability and productivity
2Reliability
If conventional glucoamylases are used, then the enzyme structure remains simple and well-characterized, but glucose tolerance is limited, affecting high-yield fermentation
Solution Approach 1:
The patent applies local quality by making targeted amino acid substitutions at specific positions (95, 59, 119, 121, 426) rather than globally modifying the entire enzyme structure. This localized approach improves glucose tolerance while maintaining overall structural simplicity and characterizability
3Productivity
If standard saccharification conditions are used, then the process follows conventional parameters, but the yield in fermentation product production is limited
Solution Approach 1:
The patent applies preliminary action by pre-modifying the glucoamylase enzyme structure through specific amino acid substitutions before the fermentation process. This preliminary structural optimization enables the enzyme to perform more effectively under improved saccharification conditions, thereby increasing fermentation product yield without complicating operational procedures
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 variants exhibit increased thermo-stability and glucose tolerance, leading to higher yields and efficiency in fermentation product production, including ethanol, from un-gelatinized starch, with improved process conditions such as higher temperature saccharification.
Implementation Method 1
Glucoamylase (1,4-alpha-D-glucan glucohydrolase, EC 3.2.1.3) is an enzyme, which catalyzes the release of D-glucose from the non-reducing ends of starch or related oligo- and polysaccharide molecules
Implementation Method 2
Glucoamylase (1,4-alpha-D-glucan glucohydrolase, EC 3.2.1.3) is an enzyme, which catalyzes the release of D-glucose from the non-reducing ends of starch
Implementation Method 3
The present invention provides glucoamylase variants with improved properties compared to its parent, comprising a substitution at one or more positions corresponding to positions 95, 59, 119, 121, 18, and 426, wherein the variant has increased thermo-stability
Implementation Method 4
The present invention provides glucoamylase variants with improved properties compared to its parent, wherein the improved properties are increased thermo-stability and increased glucose tolerance
Data Source
AI summary
The present invention relates to glucoamylase variants. The present invention also relates to polynucleotides encoding the variants; nucleic acid constructs, vectors, and host cells comprising the polynucleotides; and methods of using the variants.