Engineered Yeast Hernandulcin Biosynthesis Using NtEAH Oxidation
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Solution Overview
Problem
Current methods for producing hemandulcin, a sweet non-calorigenic sesquiterpenoid, face challenges such as low yields, impurities, and the lack of a complete biosynthetic pathway, making large-scale production difficult, especially in microbial cells like yeast.
Innovation Solution
Utilizing cytochrome P450 enzymes, such as Nicotiana tabacum 5-epi-aristolochene dihydroxylase (NtEAH) and other functional variants, to convert (+)-epi-α-bisabolol into hemandulcin within engineered yeast cells, along with heterologous (+)-epi-alpha-bisabolol synthase and cytochrome P450 reductase, to establish a microbial factory for hemandulcin production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If hemandulcin is extracted from L. dulcis plant, then hemandulcin can be obtained, but the yield is low and impurities are present
Solution Approach 1:
The patent replaces mechanical extraction methods with biological synthesis using engineered yeast cells. The yeast expresses heterologous enzymes (LdTPS8p, NtEAH, LdCPR1p) to biosynthetically produce hemandulcin, substituting the mechanical extraction process from plant material with a controlled biological manufacturing system that achieves higher yields and purity.
Solution Approach 2:
The patent uses engineered yeast cells as an intermediary system to produce hemandulcin. The yeast expresses plant-derived enzymes (LdTPS8p for bisabolol synthesis, NtEAH for oxygenation, LdCPR1p for electron transfer) to convert simple precursors into hemandulcin, serving as a biocatalytic intermediary between simple substrates and the target compound.
2Quantity of substance
If chemical synthesis of hemandulcin is performed, then hemandulcin can be produced, but the process requires six steps with only 15% overall yield
Solution Approach 1:
The patent replaces multi-step chemical synthesis with a biological catalytic system. Engineered yeast cells express enzymes that catalyze the conversion of farnesyl diphosphate to hemandulcin through the bisabolol intermediate, substituting six chemical reaction steps with a streamlined biological pathway that achieves higher overall yield and simplifies the production process.
Solution Approach 2:
The patent divides the hemandulcin biosynthesis pathway into discrete enzymatic steps expressed by separate genes in the yeast: LdTPS8p for the first step (FPP to bisabolol), NtEAH for the second step (bisabolol to hemandulcin), and LdCPR1p for electron transfer. This segmentation allows independent optimization and characterization of each step while achieving the complete transformation.
3Quantity of substance
If cell suspension cultures of L. dulcis are used for hemandulcin production, then some hemandulcin can be produced, but the addition of elicitors or precursors is required and genetic engineering tools are unavailable
Solution Approach 1:
The patent uses engineered yeast cells as an intermediary production system that is genetically tractable. The yeast expresses plant-derived enzymes (LdTPS8p, NtEAH, LdCPR1p) to produce hemandulcin, serving as a genetically engineerable intermediary that overcomes the limitation of unavailable genetic tools in L. dulcis while enabling scalable production.
Solution Approach 2:
The patent changes the host organism parameter from L. dulcis plant cells to engineered yeast cells. This parameter change enables genetic manipulation and scaling while maintaining the ability to produce hemandulcin. The yeast system allows for controlled expression of the biosynthetic pathway without requiring elicitors or complex precursor additions.
4Adaptability or versatility
If co-expression of LdTPS8p and mammalian cytochromes P450 is attempted, then various hydroxylated derivatives are formed, but hemandulcin is not produced
Solution Approach 1:
The patent applies the principle of local quality by selecting a specific P450 enzyme (NtEAH from Nicotiana tabacum) with the precise catalytic properties needed for hemandulcin production. Rather than using generic mammalian P450s that produce multiple hydroxylated derivatives, the patent uses a plant-derived P450 with localized catalytic specificity that performs the exact oxygenation reaction required to convert bisabolol to hemandulcin.
Solution Approach 2:
The patent copies the native biosynthetic pathway from L. dulcis by expressing the plant's own enzymes (LdTPS8p and NtEAH) in a heterologous host. This copying approach ensures that the enzymatic reactions faithfully reproduce the natural pathway, producing the correct product (hemandulcin) rather than off-target derivatives.
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 hemandulcin with higher yields and reduced impurities, addressing the limitations of existing methods and facilitating large-scale production in microbial cells.
Implementation Method 1
the cytochrome P450 enzyme Nicodana tabacum 5-epi-aristolochene dihydroxylase (NtEAH) as set forth in SEQ ID NO 2 is able to catalyse the conversion of (+)-epi-α-bisabolol to hemandulcin
Implementation Method 2
5-epi-aristolochene dihydroxylase (NtEAH)...capable of converting (+)-epi-α-bisabolol into hemandulcin
Data Source
AI summary
The present invention relates to microbial production of the sweet non-calorigenic sesquiterpenoid hernandulcin. Disclosed herein are yeast cells capable of producing hernandulcin and optionally hernandulcin derivatives, said yeast cells expressing at least one (+)-epi-alpha-bisabolol synthase, at least one cytochrome P450 enzyme (CYP) and at least one cytochrome P450 reductase, preferably said CYP the Nicotiana tabacum CYP 5-epi-aristolocene dihydroxylase (NtEAH) or the Datura stramonium cytochrome P450 enzyme DsEAH.