Wet Microalgae Ethanol Extraction for Low-Ash Omega-3 Miscella
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Solution Overview
Problem
Current methods for extracting proteins and omega-3 from algae using toxic solvents result in residual toxic solvents and high ash content, making the final products unsuitable for food and feed applications, particularly with microalgae like Nannochloropsis, which has a double-wall cell structure that limits solvent permeability.
Innovation Solution
A method involving an aqueous microalgae slurry with at least 65% water is mixed with ethanol, allowing extraction without drying, followed by separation and evaporation under controlled conditions to produce a non-toxic miscella with less than 15% ash and omega-3 rich extract containing at least 20% omega-3.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If toxic solvents (hexane, isopropanol, acetone) are used for extraction, then extraction efficiency is improved, but residual toxic solvents remain in the final product
Solution Approach 1:
The patent changes the key parameter of solvent toxicity by replacing toxic solvents (hexane, isopropanol, acetone) with non-toxic solvents (water, ethanol, supercritical CO2). This parameter change resolves the contradiction by maintaining extraction efficiency while eliminating harmful residues in the final product, as these non-toxic solvents can be completely removed or are already safe at residual levels.
Solution Approach 2:
The patent introduces an intermediary substance (supercritical CO2 or ethanol) that facilitates extraction without leaving harmful residues. Supercritical CO2 acts as a mediator that can be completely evaporated, while ethanol serves as a non-toxic intermediary that is safe at residual levels, thus resolving the contradiction between extraction efficiency and product safety.
2Loss of substance
If thermal conditions are used to remove solvents, then solvent removal is improved, but Omega-3 degradation occurs
Solution Approach 1:
The patent utilizes phase transition of CO2 from supercritical state to gas state through pressure reduction, enabling solvent removal without thermal degradation of Omega-3. This phase change mechanism allows complete solvent elimination while preserving the thermal sensitivity of Omega-3 components.
Solution Approach 2:
The patent replaces thermal solvent removal mechanisms with mechanical pressure control for supercritical CO2 extraction. By using pressure reduction instead of heating to remove the solvent, the method avoids thermal degradation of Omega-3 while achieving complete solvent removal.
3Ease of manufacture
If Nannochloropsis is dried to >35% dry weight before extraction, then extraction setup is simplified, but solvent permeability into double-wall cell structure decreases
Solution Approach 1:
The patent changes the moisture content parameter from low (>35% dry weight) to high (aqueous slurry with significant water content). This parameter change resolves the contradiction by improving solvent permeability into the double-wall cell structure while maintaining extraction feasibility through the use of ethanol or supercritical CO2 as the extraction medium.
Solution Approach 2:
The patent creates a composite extraction system combining aqueous slurry with ethanol or supercritical CO2. This composite approach allows extraction from wet biomass by using a solvent system that can penetrate the double-wall cell structure effectively, resolving the permeability issue without requiring complete drying.
4Productivity
If solvent-permeability enhancer (diatomaceous earth) is added to enhance extraction, then solvent permeability is improved, but ash content in miscella increases above 15% DW
Solution Approach 1:
The patent extracts and removes the solvent-permeability enhancer (diatomaceous earth) from the process entirely. By eliminating this additive, the method achieves acceptable solvent permeability through alternative means (aqueous slurry preparation or supercritical CO2) while keeping ash content below the 15% DW threshold, thus resolving the contradiction between permeability enhancement and ash content control.
Solution Approach 2:
The patent replaces the permanent addition of diatomaceous earth with a disposable or removable permeability enhancement method using aqueous preparation or supercritical fluid technology, allowing effective extraction without introducing persistent ash-containing materials into the final product.
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 method effectively extracts omega-3 and proteins from algae without toxic solvents, producing a non-toxic, low-ash miscella suitable for food and feed applications, while preserving the polar-lipid structure of omega-3.
Implementation Method 1
mixing the aqueous microalgae slurry with ethanol for a predetermined duration
Implementation Method 2
separating the aqueous microalgae slurry-ethanol mixture to liquids and miscella
Implementation Method 3
evaporating the water and the ethanol from the liquid to receive a liquid extract
Data Source
AI summary
Disclosed is a non-toxic omega-3 rich extract and non-toxic miscella and a method of producing same. The method may include obtaining an aqueous microalgae slurry comprising at least 65% water; mixing the aqueous microalgae slurry with ethanol for a predetermined duration; separating the aqueous microalgae slurry-ethanol mixture to liquids and miscella; and evaporating the water and the ethanol from the liquid to receive a liquid extract. In some embodiments, the miscella contains organic material and ash at an amount below 15 dry weight %.