A hydrogel is a hydrophilic polymer network with the ability to retain a significant amount of physical water in its structure. For example, superabsorbent polymers used in baby diapers can absorb more than 1000 times their weight in water, but even more modest levels (10 to 1000wt%) hydrogels are useful as a water management tool to control hydration levels in agricultural applications such as soil amendments or seed coatings. In the case of seed coatings, the incorporation of hydrogels has been shown to stimulate early plant growth and lead to higher crop yields. Battelle has developed a process to chemically modify soymeal such that both the protein and carbohydrate fractions become water soluble enabling utilization of the entire composite mixture rather than just the protein or just the carbohydrate. In a second conversion step, chemical crosslinks are built within the water-soluble soy flour to create a hydrogel structure. Utilizing the modified soy protein and carbohydrate fractions, a soy-based hydrogel with a high soy content (>80% dry weight), is biodegradable and can serve as a soil amendment or seed coating is targeted. In FY24, Battelle sought to determine feasibility of converting soymeal into a hydrogel for potential use in agricultural applications such as soil amendment and seed coating. Leveraging its previous development with soymeal, Battelle initiated the evaluation of approaches to improve the process of converting soy flour into a more water-soluble form. This involved both pretreatments and varying reaction conditions to maximize the soy flour water solubility at neutral pH. Forming a hydrogel from modified soy flour involves creating a physical network or crosslinked structure that absorbs water without becoming dissolved. Ionic crosslinking via calcium and covalent acylation are two crosslinking strategies that have been pursued thus far and have resulted in unoptimized, weak gels with minor water uptake. Refinement of the crosslinking, characterizing the hydrogel performance and validating their use in agricultural applications will be the initial emphasis in the next phase of work.

This project creates value for the soybean farmer by creating new uses for soymeal as a hydrogel which can be used as a water management tool to control hydration levels in agricultural applications such as soil amendments or seed coatings. The overall objective is to commercialize this technology through licensing to a company, providing a monetary return via a licensing royalty and driving the increased utilization of soy-based feedstocks.