New carbon-negative building material could one day replace concrete

Researchers at Worcester Polytechnic Institute have developed Enzymatic Structural Material (ESM), a carbon-negative alternative to conventional concrete that captures and solidifies carbon dioxide into a durable building material. Led by Nima Rahbar, the team utilized the enzyme carbonic anhydrase—naturally found in human red blood cells—to accelerate the conversion of CO2 and water into carbonic acid, which then reacts with calcium to form calcite crystals. These crystals bind sand and carbon into a rock-like matrix, mimicking natural processes seen in seashells and reefs. Unlike traditional concrete, which emits significant CO2 and requires 28 days to cure, ESM sequesters carbon (about 6.1 kg per cubic meter) and can be molded within hours under mild, energy-efficient conditions. ESM demonstrates impressive mechanical properties, with an average compressive strength of 25.8 MPa, surpassing minimum standards for structural concrete, and maintains durability even when exposed to water. This rapid curing and