Recombinant Host Steviol Glycoside Production
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Solution Overview
Problem
The recovery and purification of steviol glycosides from the Stevia plant are labor-intensive and inefficient, resulting in compositions with off-flavors due to plant-derived components, and there is a need for improved production methods that can produce high yields of specific steviol glycosides with reduced plant-derived impurities.
Innovation Solution
A recombinant host cell capable of producing steviol glycosides is developed, equipped with a polypeptide that can glycosylate steviol or its precursors at specific positions, such as the C-19 carboxyl group, with specific amino acid substitutions, along with genes for synthesizing key intermediates in the steviol glycoside biosynthetic pathway, allowing for enhanced production and purification of desired steviol glycosides like RebD and RebM.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional extraction methods are used to obtain steviol glycosides from Stevia plant, then the process is simple to implement, but the recovery and purification are labor-intensive and inefficient, resulting in compositions with off-flavors due to plant-derived components
Solution Approach 1:
The patent extracts only the desired steviol glycosides from the Stevia plant through selective purification processes, separating them from unwanted plant-derived components that cause off-flavors. This is achieved through chromatographic techniques and selective crystallization that isolate specific glycosides while removing impurities.
Solution Approach 2:
The patent employs parameter changes in purification processes, such as adjusting pH, temperature, and solvent composition during extraction and purification steps. These parameter modifications optimize the separation efficiency and enable selective recovery of desired steviol glycosides while eliminating off-flavor compounds.
2Quantity of substance
If recombinant production system is implemented to produce steviol glycosides, then high yields of desired steviol glycosides can be accumulated with reduced plant-derived components, but the device complexity and production process become more complex
Solution Approach 1:
The patent uses recombinant microorganisms as intermediary factories that contain the complete biosynthetic pathway for steviol glycoside production. These engineered hosts serve as living bioreactors that convert simple substrates into complex steviol glycosides through expressed plant enzyme pathways, simplifying the overall production process while maintaining high yields.
Solution Approach 2:
The patent divides the complex biosynthetic pathway into discrete enzymatic steps, each catalyzed by a specific recombinantly expressed enzyme. This segmentation allows for modular optimization of each pathway step and enables independent tuning of enzyme expression levels to maximize productivity while managing system complexity.
3Manufacturing precision
If enzymes with 19-O glycosylation activity are used to produce steviol glycosides, then specific steviol glycosides can be produced, but the catalytic capability needs to be increased to produce higher yields
Solution Approach 1:
The patent modifies enzyme parameters through site-directed mutagenesis to optimize both specificity and catalytic activity. Amino acid substitutions in the enzyme active site enhance substrate binding affinity and catalytic efficiency, allowing high-yield production of specific steviol glycosides while maintaining position-selective glycosylation.
Solution Approach 2:
The patent introduces specific amino acid substitutions at key positions in the enzyme structure to enhance catalytic capability at the active site while maintaining overall enzyme stability and specificity. These localized modifications improve turnover numbers and substrate affinity without compromising the enzyme's selective glycosylation ability.
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
This approach enables the production of steviol glycosides with reduced plant-derived components, achieving higher yields and improved purity, and allows for the specific enhancement of certain steviol glycosides, addressing the inefficiencies of traditional extraction methods.
Implementation Method 1
a polypeptide capable of glycosylating steviol or a steviol glycoside at its C-19 carboxyl group
Data Source
AI summary
The invention relates to recombinant microorganisms and methods for producing steviol glycosides and steviol glycoside precursors.