How A Seafood Waste Stream Is Being Transformed Into A Multi-Use Biopolymer

Overall, our modern food system does a good job of preventing resource waste by finding ways to utilize the various byproducts that it generates along the way. Often those streams can be even further “upcycled” from low value uses to higher value applications. There is a recent example of what was a major waste-stream that is now being tapped as the basis for a wide range of useful products. The product is a biopolymer called chitosan which can be made from the shells of crustaceans – e.g., crabs, lobsters, and shrimp. When those animals are processed to make consumer-level products, the shells were typically treated as waste that was either dumped in the ocean, incinerated, or sent to landfills. Two individuals who were involved in the seafood industry (Craig Kasberg and Zach Wilkinson) were independently looking into the potential to find a better use for the shells because they were bothered about that and other waste issues. A mutual friend introduced them because he had heard them both talking about chitosan. They ended up starting a company called Tidal Vision which subsequently worked out a novel and scalable method to extract chitosan from the shells.

Background biology: The hard outer shells of crustaceans are made of something called chitin, the second most abundant polymer on the planet, after cellulose from plants. Chitin then undergoes a deacetylation process to become chitosan, where it then has some unique and interesting properties because of its “cationic” (positive) charge. This gives it the capacity to form an ionic bond with any chemical that has an “anionic” (negative) charge. This natural chemical has been known and used for a long time, but it was always relatively expensive. The Tidal Vision proprietary chitin and chitosan extraction method uses recyclable “green chemistry” solvents and generates a usable fertilizer byproduct in addition to the chitosan. This lower cost chitosan has been a game changer because suddenly there are so many more practical uses, with at least 400 potential applications being identified so far. One of the reasons for this breadth of uses is that chitosan can exist in various forms. It is possible to generate different chain lengths of the polymer and different degrees of “de-acetylation.”

Tidal Vision has been growing rapidly, but it has to prioritize its resources. The current focus is on three major categories of use for chitosan which are branded as Tidal Clear, Tidal Grow and Tidal Tex.

Tidal Clear is the brand for the water treatment industry, and that is the most active part of the company’s business today. Chitosan is very effective as a “flocculant” because its cationic binding capability allows it to pull together various particulates so that they will either settle out or be easier to remove by filtering. Chitosan is a new alternative flocculant for clarification of water coming into a water treatment facility and also for filtering out the biosolids from water so that it can be recycled after sewage treatment. It can also be used as a pool clarifier. In animal processing facilities chitosan can be used to recover fats or other potential nutrients from the wash water. In fruit and vegetable packing operations it helps with recycling the wash water. In these cases, the chitosan is often replacing aluminum sulfate or greatly reducing the amount of that which is needed.

Tidal Grow is a category for agricultural uses. Chitin is found in the cell walls of fungi and it makes up the “exoskeleton” of insects. Plants have various ways to detect fungal and insect pests in order to ramp up their natural defense systems, and chitosan is able to elicit that reaction as part of an overall bio stimulant effect. Tidal Vision is about to launch a chitosan-based seed treatment product for this purpose. Chitosan can also provide “biocontrol”, meaning that it can bind to microbes and inhibit them from reproducing. Chitosan can also be used to deliver crop protection products more effectively, like copper hydroxide, which is among the few available options for bacterial diseases in crops like citrus and walnuts, but which normally washes off plants too easily. The company is investigating other ways that chitosan can be used to enhance the performance of other trusted crop protection and fertilizer products.

Tidal Tex is the company’s brand for textiles use, where it offers a low toxicity option to replace metal-based and synthetic chemicals used as fire retardants, anti-microbials or anti-odorants. Millions of pounds of these products are used on everything from clothing to furniture to mattresses to automobile door linings. Chitosan is also useful as a “dye mordant” for making colored fabric. In June of 2021 Tidal Vision announced a partnership with Leigh Fibers and the opening of a new production facility in South Carolina to make chitosan formulations that are plug-on options specifically for the textile industry. Leigh Fibers is a leader in the industry with regard to the manufacturing of engineered fiber solutions, as well as processing of textile waste for desirable purposes.

In terms of future applications, Tidal Vision cooperates with potential customers to identify and supply samples of forms of chitosan solutions likely to fit their needs. When new fits are identified they arrange non-exclusive supply agreements moving forward.

So what was once just a problematic waste stream is now a source of naturally-based ingredients with scores of valuable uses.