Students from Danang University of Science and Technology Create Cement-like Adhesive Using Urease Enzyme Extracted from Soybeans
Since mid-2020, Quoc Anh and Huu Hoang have been researching how to produce biological cement. The team selected soybeans and discovered that the urease enzyme contained in the beans has excellent adhesive properties. According to the team, this enzyme is commonly found in microorganisms and plants, but it is present in higher concentrations in soybeans.
The team extracted a urease enzyme solution from soybeans and then injected it into sand samples. After one hour, they removed the enzyme solution from the samples and injected a mixture of Urea + CaCl2 (in a 1:1 ratio). From this, the calcium carbonate (CaCO3) generated in the biochemical reactions binds the sand particles together.
“In addition to binding, the precipitation of CaCO3 will also fill the voids between the sand grains, reducing the permeability of the sand mass,” Quoc Anh explained. Once the sand mass solidifies, its compressive strength is increased, and its reduced permeability enhances stability, minimizing particle erosion caused by seepage through the sand mass.
According to the research team, this adhesive can be used to reinforce areas of coastal erosion, as it can solidify sand in those regions, thereby reducing construction costs for embankments.
The process of creating biological cement from soybeans helps bind sand into a solid, waterproof mass. (Image: NVCC)
In the construction industry, this type of biological cement can be used to create bricks by pouring the adhesive into sand molds and then shaping it. “The traditional brick production process involves firing, which generates CO2 emissions that pollute the environment, and it relies on fossil fuels to produce cement. Therefore, the team aims to create a plant-based, environmentally friendly material that can replace traditional cement,” shared Nguyen Le Quoc Anh, the team leader, explaining the motivation behind their research.
Initially, when the team extracted the urease enzyme from soybeans, fine particles appeared, resulting in low purity levels of the solution. This led to inconsistent quality and adhesion in the sand columns used for experimentation.
The team has since improved the enzyme extraction process by centrifuging the entire solution after extraction at a speed of 4000 RPM. This enhancement allows the urease enzyme extracted from soybeans to perform better and increases its potential for use as a material for biological cement.
The team conducted experiments to measure the compressive strength and permeability of the sand after solidification through unconfined compression tests, soil permeability assessments, and microstructural analyses (SEM and XRD), while also evaluating the economic and environmental sustainability of the product. The results indicate that the biological cement material from soybeans meets several conditions for application in reinforcing eroded coastal areas and foundation stabilization…
Member Ngo Huu Hoang believes that biological cement holds promise as an adhesive that could replace conventional Portland cement for future construction projects.
The team has so far only applied it to standard sand as per TCVN 6227:1996. Hoang stated that in the near future, they will use biological cement to solidify natural sand, specifically beach sand in the Danang area, while also initially testing its erosion resistance on slope models for foundation reinforcement in construction.
Commenting on the research, Dr. Hoang Phuong Tung, a lecturer from the Department of Civil Engineering at Danang University of Science and Technology, noted that research on biological cement has been conducted by the scientific community worldwide for many years. In the United States and Europe, companies have already produced certain types of wall tiles and solidified sand using this technology.
Domestically, he pointed out that there are not many studies on biological cement adhesives, making the team’s direction highly promising and applicable. “However, to apply biological cement in construction projects, the team needs to optimize the production techniques and ensure the preservation of biological raw materials, as well as standardize the formulas for different types of materials,” Dr. Tung advised.
