Hybrid Yeast Strain for High-Solids Ethanol Fermentation
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Solution Overview
Problem
Existing yeast strains used for ethanol production face challenges such as slow growth rate, reduced robustness, inability to grow in high dry solids conditions, and increased production of undesirable by-products, limiting their efficiency and economic viability in fuel ethanol production.
Innovation Solution
Development of hybrid yeast strain Saccharomyces cerevisiae DGY1, engineered with reduced Dls1 expression and additional genetic modifications, including alternative pathways for ethanol production, to enhance ethanol yield and robustness under high dry solids and elevated temperature conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If engineered yeast is used to increase ethanol production, then ethanol yield is improved, but growth rate and robustness deteriorate
Solution Approach 1:
The patent divides the yeast genome into multiple chromosomal loci, distributing five different carbohydrate processing enzyme genes across five separate locations. This segmentation allows each gene to be independently optimized and expressed without interfering with each other, maintaining cellular robustness while achieving high ethanol production through cumulative enzymatic activity
Solution Approach 2:
The patent combines multiple parental yeast strains to create a hybrid that merges desirable traits from each parent. The hybrid yeast inherits robust growth characteristics from one parent and enhanced carbohydrate processing capabilities from the other, achieving both high robustness and high ethanol yield simultaneously
2Productivity
If metabolic engineering is applied to increase ethanol production, then ethanol yield is improved, but production of undesirable byproducts increases
Solution Approach 1:
The patent extracts and eliminates the DLS1 gene from the yeast genome, which is responsible for producing excessive glycerol and acetate byproducts. By removing this specific genetic element, the yeast redirects metabolic flux toward ethanol production, increasing ethanol yield while simultaneously reducing harmful byproduct formation
Solution Approach 2:
The patent modifies key metabolic parameters by introducing multiple carbohydrate processing enzyme genes that alter the yeast's metabolic pathway efficiency. These genetic modifications change the metabolic parameters to favor ethanol production over byproduct formation, achieving high ethanol yield with reduced glycerol and acetate production
3Productivity
If yeast is engineered for high ethanol production, then ethanol yield is improved, but ability to grow in high dry solids conditions deteriorates
Solution Approach 1:
The patent merges two parental strains where one contributes robustness to high dry solids conditions and the other contributes enhanced carbohydrate processing capabilities. The resulting hybrid yeast inherits both traits, achieving the ability to grow in high dry solids environments while maintaining high ethanol production capacity
Solution Approach 2:
The patent distributes five different carbohydrate processing enzyme genes across five separate chromosomal loci, allowing each gene to be independently optimized for expression under high dry solids conditions. This segmented approach enables the yeast to maintain robust growth while achieving high ethanol yield through cumulative enzymatic activity
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 hybrid yeast strain DGY1 demonstrates increased ethanol production by 2-5% compared to parental strains, improved robustness, and reduced glycerol and acetate production, making it suitable for efficient fuel ethanol production.
Implementation Method 1
fermenting the glucose to produce ethanol using a fermentation organism
Data Source
AI summary
Described are compositions and methods related to hybrid yeast that produces an increased amount of ethanol from starch-containing substrates compared to its parental yeast. Such yeast is well-suited for use in fuel alcohol production to increase yield.