The ATPS Extraction Method

When it comes to botanical extraction, deciding which extraction technique is the best requires evaluating several variables. On the manufacturing side, details like equipment, solvents, or energy requirements can play a role, but there are also questions about the final product to consider as well. Some companies may find it more beneficial to invest in better practices designed to increase their yields or minimize their environmental impacts. 

With this in mind, one of the best extraction techniques may be Aqueous Two Phase Systems (ATPS) extraction, which relies on basic physical properties of the solvent to effectively isolate compounds in a solution. [1] The technique itself is relatively simple, but there is a large amount of adaptability that may better address more customized needs. As a result, ATPS extraction is proving vital to multiple industries that rely on botanical extraction to develop their products. 

What is an ATPS Extraction Method

Picture a jar filled with a solution that is equal parts oil and water. If the jar is shaken, the two liquids may temporarily blend, but they don’t stay that way. When left to sit for an extended amount of time, those two components will naturally separate back into their two layers, each one distinct from the other. The reason oil and water don’t mix with each other comes down to the molecular structures of the two substances. Oil is made up of fats, whereas water consists of hydrogen atoms bonded with oxygen. When the jar is shaken up, individual fat molecules may go in between the water molecules, but they don’t break any hydrogen bonds that would break the water molecules apart from the oxygen. [2] 

Since the molecular bonds aren’t actually breaking, the blended solution separates based on density. Water molecules are denser than the lipids in the oil, so they sink to the bottom. In this process, the steps involve mixing the solution, followed by a period of separation. Imagine if, during the mixing period, botanical material could be absorbed into the solution, with various components bonding to specific solvents, before the inevitable separation of the components.

This is the general concept behind ATPS extraction. Though it is simple in design the practice becomes a little more complicated. With most ATPS extractions, there needs to be some kind of catalyst that prompts the separation to occur. To do this, a variable in the solution, like PH, temperature, or ionic bonds, is altered within the solution. [3] [4][1][5] The last variable, Ionic bond changes, can happen with the introduction of new materials into the solution like alcohols or salts that cause polarity. Introducing the catalyst prompts the separation of the solution into its various layers.

To keep things even more interesting, it is also possible to add second or third catalysts to separate solutions into more layers, but that may depend on what kinds of solvents, organic materials, and available equipment. Regardless of how many catalysts or separations that are ultimately employed, the final stage of the extraction involves isolating the layers and thus separating the desired extraction material. The full process entails the solution mixing, absorption into the solution, and the ultimate separation of the polymers.

Benefits of ATPS

ATPS extraction is not difficult, and as a result has become a relatively common extraction strategy. As a result of this simplicity and ubiquity, there are a lot of advantages that have been identified when it comes to ATPS extraction. Certain advantages will vary based on specific details of the extraction, but there are some commonalities. 

For starters, ATPS extraction is fast and inexpensive. [6] During the extraction procedure, the absorption phase may take some time, but the catalyst, separation, and isolation should happen quickly. Catalysts vary, but they may entail adding heat or salts to the solution. Compared to other extraction methods, which may rely on complex equipment or extended extraction times, ATPS extraction can improve both speed and cost. Additionally, ATPS extraction tends to rely on water based solvents, compared to more harmful solvents that other extraction methods may rely on.

Using water based solvents can provide advantages for both customers and manufacturers. For consumers, there are fewer risks associated with water based solvents, especially if the products are meant for human consumption. This may depend on the intended use of the product, but water is safer than many other solvents for human exposure. 

On the manufacturing end, water is a cheap solvent that can be reused multiple times. Not only does this benefit the bottom line by lowering operating costs, but it can also minimize the environmental impact, which may serve as a marketing point. Additionally, manufacturers may find that ATPS extraction can increase the potency of their extracts as well by minimizing any potential molecular damage that could have resulted from exposure to other solvents. [7]

This means that manufacturers are able to lower their costs, reuse their materials, and provide better products to customers at the same time. By tweaking variables like solvents or catalysts, manufacturers may be able to further customize their extraction procedures to better focus on an aspect of production like sustainability or consumer safety, if they so choose.

This customization serves as one of the greatest advantages to ATPS, because systems can be developed that are either very simple or very complex, depending on what may be needed. This may involve additional equipment, faster saturation times, altered catalysts, solvents, or botanical material, and more. It may also be possible to augment the procedure with things like ultrasonication or improved solvent combinations like using alcohol and salt combinations to produce better yields. [8][9] This massive amount of adaptability means that any manufacturer can design an ATPS extraction technique that fulfills their exact needs efficiently.

As a result, if the extraction system can be customized, it can also be scaled. This means that if manufacturers design a system that works for them, it is possible to scale up the equipment to increase production further. In fact, depending on the needs of the extraction, it may be possible to have a solution set up that is constantly absorbing, separating, and isolating components for a non-stop extraction of biological materials. All of these aspects add up to lower costs, lower environmental impact, better products for customers, and a high potential to customize and scale operations to match any extraction company’s needs.

Ways to Use ATPS Extraction

It can be difficult to specify aspects of ATPS extraction because of how customizable it can be. All of these variables are beneficial for the extractor, but it can be difficult to understand how one of these systems can best be employed. Instead of focusing on the specifics within a particular ATPS extraction system, it may be better to look at some real use cases to understand how it is being utilized. One of the most common ways in the botanical extraction industry revolves around food production. [10] 

ATPS has been used to separate and extract all sorts of useful compounds from organic materials. This may come in the form of isolating proteins, increasing fiber, or limiting carbohydrates and sugars within the original food source. Food manufacturers looking to utilize these systems may be able to alter their products on a molecular level to increase nutritional properties or flavors to better address market needs.

The same also applies to feedstocks that may also be used to feed livestock instead of humans as well. [11] Feedstock is similar to food production, but the goal of these two different food sources is different. Food intended for humans may alter their products to meet specific nutritional needs, whereas food meant for livestock may be intended only to fatten up the animals. 

Different goals should mean different procedures, but the general practices may be similar. Going beyond food, plant material extracts can provide health benefits in other ways besides eating them. A lot of plant material, including vitamins and minerals, are used for health supplements and in many medications. In fact, estimates are that between 25-40% of all pharmaceuticals rely on plant materials for their production. Because of this, ATPS extraction is also being utilized in the pharmaceutical industry. [12] This could also be in the form of basic materials or ingredients like lipids that may need to be extracted. 

The same can be true for a lot of plant material that goes into the production of dyes and color products.[13] Depending on what the dies are used for, the plant material extracted with ATPS extraction could be used for either the cosmetic or textile industries. The biological material needed to make these bright colors faces less risk of damage when using ATPS extraction compared to other extraction methods. Though food, pharmaceuticals, cosmetics, textiles are good starts, this is only the beginning for how ATPS extraction is changing industries using organic extraction to develop new materials. 

Though research is still early, it is possible that certain plant materials may be able to use ATPS extraction to replace fossil fuels in several heavy industries. This could involve using sugar, lipids, and fungi to develop fermented biofuels, starch from algae to make bioplastics, or polysaccharides to create biopolymers for various industrial applications. [14][15][16] 

This may seem like it is getting into the realm of science fiction, but as long as there is a push for green sustainable practices, it is possible that ATPS extraction may play a role in developing better ways to fill these industrial needs.

References:

1. Iqbal, Mujahid, et al. “Aqueous two-phase system (ATPS): an overview and advances in its applications.” Biological procedures online 18 (2016): 1-18.Silverstein, Todd P. “The real reason why oil and water don’t mix.” Journal of chemical education 75.1 (1998): 116.
2. Silverstein, Todd P. “The real reason why oil and water don’t mix.” Journal of chemical education 75.1 (1998): 116.
3. Pietruszka, N., et al. “New polymers forming aqueous two‐phase polymer systems.” Biotechnology progress 16.3 (2000): 408-415.
4. Ferreira, Juliana Ferrari, José Carlos Curvelo Santana, and Elias Basile Tambourgi. “The effect of pH on bromelain partition from Ananas comosus by PEG4000/phosphate ATPS.” Brazilian Archives of Biology and Technology 54 (2011): 125-132.
5. Xu, Wenzhuo, et al. “Ionic-Liquid-Based Aqueous Two-Phase Systems Induced by Intra-and Intermolecular Hydrogen Bonds.” Molecules 27.16 (2022): 5307.
6. Torres-Acosta, Mario A., et al. “Economic analysis of the production and recovery of green fluorescent protein using ATPS-based bioprocesses.” Separation and Purification Technology 254 (2021): 117595.
7. Nouri, Erfan, and Gholam Khayati. “A Review of Background and Application of ATPSs in Protein and Enzyme Extraction.” Journal of Solution Chemistry (2024): 1-35.
8. Liao, Longren, et al. “Ultrasonication followed by aqueous two-phase system for extraction, on-site modification and isolation of microalgal starch with reduced digestibility.” Ultrasonics Sonochemistry 106 (2024): 106891.
9. Tan, Zhi-jian, Fen-fang Li, and Xue-lei Xu. “Extraction and purification of anthraquinones derivatives from Aloe vera L. using alcohol/salt aqueous two-phase system.” Bioprocess and biosystems engineering 36 (2013): 1105-1113.
10. Khan, Bilal Muhammad, Kit-Leong Cheong, and Yang Liu. “ATPS:“Aqueous two-phase system” as the “answer to protein separation” for protein-processing food industry.” Critical reviews in food science and nutrition 59.19 (2019): 3165-3178.
11. Selvakumar, Pitchaivelu, et al. “A practical implementation and exploitation of ATPS for intensive processing of biological feedstock: a novel approach for heavily biological feedstock loaded ATPS.” Separation and purification technology 75.3 (2010): 323-331.
12. Xu, Yan, et al. “Liquid-liquid extraction of pharmaceuticals by aqueous two-phase systems.” Braz. J. Pharm. Sci 37.3 (2001): 305-320.
13. Borges, Gabriella Alexandre, et al. “A method for dye extraction using an aqueous two-phase system: Effect of co-occurrence of contaminants in textile industry wastewater.” Journal of environmental management 183 (2016): 196-203.
14. Huang, Wei-Dong, and Y-H. Percival Zhang. “Analysis of biofuels production from sugar based on three criteria: Thermodynamics, bioenergetics, and product separation.” Energy & Environmental Science 4.3 (2011): 784-792.
15. Di Caprio, Fabrizio, et al. “Microalgae Biorefinery: Optimization of Starch Recovery for Bioplastic Production.” ACS Sustainable Chemistry & Engineering 11.46 (2023): 16509-16520.
16. Macagnan, Karine Laste, Mariane Igansi Alves, and Angelita da Silveira Moreira. “Approaches for enhancing extraction of bacterial polyhydroxyalkanoates for industrial applications.” Biotechnological Applications of Polyhydroxyalkanoates (2019): 389-408.