Recombinant Yeast Strain Engineering for High-Yield Cholesterol Production
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Solution Overview
Problem
Existing yeast strains are limited in their ability to produce cholesterol and cholesterol precursors in high yields, and there is a need for a recombinant yeast strain that can efficiently produce these compounds without interfering with foreign metabolic pathways.
Innovation Solution
A recombinant yeast strain is developed by deleting ERG5 and ERG6 genes and introducing DHCR24 and DHCR7 genes, optionally with codon optimization, and further enhancing production by adding tHMG1, ERG2, ERG5, ERG27, or UPC2-1 genes, using a multiple gene integration cassette with specific promoter regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If existing yeast strains are used for cholesterol production, then the production process is simple, but the yield of cholesterol and cholesterol precursors is limited
Solution Approach 1:
The patent divides the cholesterol biosynthesis pathway into specific gene targets (ERG5, ERG6 for deletion and DHCR24, DHCR7 for introduction), allowing precise modification of individual genes rather than attempting to modify the entire pathway at once. This segmentation enables systematic optimization of cholesterol production while managing the complexity of genetic engineering.
Solution Approach 2:
The patent introduces codon-optimized versions of DHCR24 and DHCR7 genes, changing the nucleotide sequence parameters to match yeast codon preferences. This parameter change enhances gene expression efficiency and enzyme activity, directly improving cholesterol yield without requiring complex pathway restructuring.
2Productivity
If multiple genes are introduced to enhance cholesterol production, then the yield increases, but the risk of interfering with foreign metabolic pathways increases
Solution Approach 1:
The patent deletes ERG5 and ERG6 genes from the yeast genome, removing the native ergosterol synthesis pathway that would compete with cholesterol production. By taking out these interfering genes, the metabolic pathway is simplified to favor cholesterol and precursor accumulation, reducing metabolic conflicts while maintaining pathway stability.
Solution Approach 2:
The introduced DHCR24 and DHCR7 genes act as intermediaries that convert existing yeast metabolites (ergosterol precursors) into cholesterol and its precursors. These intermediary enzymes bridge the gap between yeast native metabolism and desired cholesterol production, allowing efficient conversion without requiring complete pathway replacement.
3Productivity
If gene copy number is increased to improve production, then the productivity increases, but the difficulty of controlling gene expression increases
Solution Approach 1:
The patent introduces multiple copies of DHCR24 and DHCR7 genes into the yeast genome to ensure sufficient enzyme activity for high-level cholesterol production. By using partial redundancy (multiple copies rather than single optimized genes), the system achieves robust overexpression that compensates for variable expression levels, maintaining high productivity while simplifying control.
Data Source
AI summary
The present invention relates to a recombinant yeast strain having sterol productivity, a preparation method therefor and a use thereof, and more specifically, to a recombinant yeast strain capable of producing cholesterol and cholesterol precursors in a high yield through the deletion of ERG5 and ERG6 genes and the introduction of DHCR24 and DHCR7 genes by codon-optimizing same in multiple or with a codon context method; and a production method therefor and a use thereof. In addition, disclosed are: a method for producing a recombinant yeast strain with increased production yields of cholesterol and cholesterol precursors by the additional introduction of gene tHMG1, ERG2, ERG3, ERG27, or UPC2-1 in the prepared recombinant yeast strain; and a use thereof.