Yarrowia Lipolytica Strain Engineering for High EPA Yield
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Solution Overview
Problem
Current methods for producing eicosapentaenoic acid (EPA) using microbial sources face challenges in improving yield and controlling oil composition, with existing microbial production methods relying on natural abilities of microorganisms, leading to inefficient and costly large-scale fermentation, and fish oil alternatives suffer from heterogeneity, unpleasant taste, environmental contaminants, and supply fluctuations.
Innovation Solution
Engineering a recombinant strain of Yarrowia lipolytica with specific genetic elements from the ω-3/ω-6 fatty acid biosynthetic pathway, including genes encoding Δ6 desaturase, C18/20 elongase, Δ5 desaturase, and Δ17 desaturase, or alternative pathways with Δ9 elongase, Δ8 desaturase, and Δ5 desaturase, to enhance EPA production beyond 25% of total fatty acids, allowing for controlled metabolic engineering and increased productivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If natural microbial sources are used for EPA production, then the process is simpler, but the yield and control over oil composition are insufficient
Solution Approach 1:
The patent applies parameter changes by modifying the genetic composition of the microbial host through recombinant DNA technology. Specific genes encoding desaturases (Δ6, Δ5, Δ17), elongases (C18/20), and other fatty acid pathway enzymes are introduced or overexpressed to alter the fatty acid biosynthesis parameters, thereby increasing EPA yield from trace levels to over 25% of total fatty acids while maintaining a controlled production process.
Solution Approach 2:
The patent creates a composite biological system by combining multiple heterologous genes from different organisms (plants, fungi, bacteria) into a single microbial host (Yarrowia lipolytica or Escherichia coli). This composite genetic architecture enables the host to perform multiple functions simultaneously - synthesizing EPA through coordinated action of desaturases, elongases, and other enzymes that originate from diverse biological sources.
2Quantity of substance
If fish oil is used as EPA source, then EPA is naturally available, but the oil has heterogeneous composition, unpleasant taste, and environmental contaminants
Solution Approach 1:
The patent extracts only the beneficial EPA component from the complex fish oil matrix by using genetically engineered microbes as a alternative production system. This eliminates the need to process heterogeneous fish oil while obtaining pure EPA, removing unwanted components such as unpleasant tastes, odors, and environmental contaminants like heavy metals and PCBs.
Solution Approach 2:
The patent replaces expensive, contaminated fish oil with a sustainable microbial production system using organisms like Yarrowia lipolytica or Escherichia coli. These microbes can be rapidly cultivated, genetically modified, and processed to produce EPA free from environmental contaminants, providing a cleaner and more controllable source.
3Ease of operation
If conventional microbial fermentation is used, then cultivation is possible, but large-scale fermentation is expensive and difficult
Solution Approach 1:
The patent enables the microbial host to self-produce EPA through its own metabolic pathways by introducing the necessary genetic machinery. The engineered microbes autonomously synthesize EPA using standard carbon sources and nutrients, eliminating the need for complex external intervention or expensive specialized cultivation conditions, thereby simplifying large-scale production.
4Reliability
If existing microbial pathways are used, then natural synthesis occurs, but the EPA concentration cannot be substantially improved
Solution Approach 1:
The patent performs preliminary genetic engineering actions before fermentation to establish high EPA-producing capabilities in the microbial host. By pre-introducing and optimizing the expression of heterologous genes for desaturases, elongases, and other pathway enzymes, the system is prepared in advance to efficiently convert carbon sources to EPA, achieving concentrations exceeding 25% of total fatty acids.
Solution Approach 2:
The patent introduces dynamic control over fatty acid biosynthesis by using inducible promoters and regulated expression systems. This allows the metabolic pathway to be dynamically adjusted during different growth phases - maintaining cell growth during exponential phase and directing carbon flux toward EPA accumulation during stationary phase, thereby maximizing overall productivity.
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 engineered Yarrowia lipolytica strain achieves high-level production of eicosapentaenoic acid, exceeding 25% in total oil fraction, enabling commercial-scale, efficient, and controlled production of EPA, addressing the limitations of natural microbial and fish oil sources.
Implementation Method 1
a) at least one gene encoding Δ6 desaturase; and, b) at least one gene encoding C18/20 elongase; and, c) at least one gene encoding Δ5 desaturase; and, d) at least one gene encoding Δ17 desaturase
Data Source
AI summary
Engineered strains of the oleaginous yeast Yarrowia lipolytica capable of producing greater than 25% eicosapentaenoic acid (EPA, an ω-3 polyunsaturated fatty acid) in the total oil fraction are described. These strains comprise various chimeric genes expressing heterologous desaturases, elongases and acyltransferases and optionally comprise various native desaturase and acyltransferase knockouts to enable synthesis and high accumulation of EPA. Production host cells are claimed, as are methods for producing EPA within said host cells.